Interstate 25 is the primary north-south freeway route along the foothills of the Front Range in the state of Colorado. Since the freeway covers nearly 300 miles of the Centennial State, the page has been split into the following segments:
This sign, which is posted very close to the Denver-Adams County Line, indicates that the next exit along northbound Interstate 25/U.S. 87 is Exit 215, Junction Colorado 53 (58th Avenue). Photo taken 08/29/04.
The right two lanes of northbound Interstate 25 are exit only for Exit 215, Junction Colorado 53, 58th Avenue. Use 58th Avenue west to connect to northbound Colorado 53/Bancock Street to Broadway. To the east, use 58th Avenue to the Merchandise Mart, Washington Street, and Riverside Cemetery (via southbound York Street). To Commerce City, use 58th Avenue east to York Street south to Colorado 265/Brighton Road northeast. Photo taken 08/29/04.
The center of Interstate 25 carries a dual, reversible, high occupancy vehicle lane to shuttle traffic between the Boulder Turnpike (U.S. 36) and downtown Denver. Photo taken 08/29/04.
Northbound Interstate 25/U.S. 87 reaches Exit 215, Junction Colorado 53, 58th Avenue to Broadway. It is not clear why Colorado 53 is a state highway, but in looking at the 1957 Gousha map, it appears that Broadway used to end at Clear Creek, without connecting to Colorado 224 (70th Avenue), but the 1968 Colorado official map shows Colorado 53 in place, with a clear connection over the creek to 70th Avenue. So it appears that the state added this route to its system once the Clear Creek bridge was constructed sometime between 1957 and 1968. Photo taken 08/29/04.
The center high occupancy vehicle lanes prepare to split, with the left lanes connecting to U.S. 36 and the right lane transitioning onto northbound Interstate 25/U.S. 87. Meanwhile, on the mainline, Interstate 25/U.S. 87 next approaches two major interchanges: Exit 216, Junction Interstate 76 east to Fort Morgan and west to Grand Junction (with a connection to Colorado 224/70th Avenue), and Exit 217, Junction U.S. 36/Denver-Boulder Turnpike. Photo taken 08/29/04.
Meanwhile, in the high occupancy vehicle lanes, these signs point to the three points of egress from the managed lanes: Colorado 224, U.S. 36, and Interstate 25/U.S. 87. Photo taken 11/12/05.
The Western Interstate 76 roughly follows the original alignment of U.S. 6 (and the South Platte River) between Denver and Sterling via Fort Morgan. Northeast of Sterling, Interstate 76 merges directly onto eastbound Interstate 80 in Nebraska, continuing along that route toward Ogallala, North Platte, Grand Island, Lincoln, and Omaha. Prior to 1975, Interstate 76 in Colorado was known as Interstate 80S, but it was changed as part of a nationwide program to eliminate most (but not all) letter-suffixed routes in the Interstate System. Photo taken 08/29/04.
This mileage sign provides the distance to the next three exits: Exit 216, Junction Interstate 76; Exit 217, Junction U.S. 36 west; and Exit 219, 84th Avenue. Notably, there is no connection currently from northbound Interstate 25 to eastbound Interstate 270/U.S. 36. This stretch of Interstate 25 through western Adams County was reconstructed as part of the Mousetrap and related construction projects in the 1990s and 2000s. Photo taken 11/12/05.
The right two lanes become exit only for the connection to Exit 216, Junction Interstate 76 east/west. Interstate 76 travels almost 184 miles in the state of Colorado, but only four of those miles reside west of Interstate 25. From here, Interstate 76 west offers another route to Interstate 70 west to the mountains west of Denver. Photo taken 08/29/04.
Now on the transition ramp onto Interstate 76, the left lane will connect to westbound Interstate 76, while the right lane connects onto eastbound Interstate 76 to Fort Morgan, Sterling, and Nebraska. Photo taken 08/29/04.
Back on the mainline, the next four exits on northbound Interstate 25/U.S. 87 are Exit 217, Junction U.S. 36/Denver-Boulder Turnpike west; Exit 219, 84th Avenue; Exit 220, Thornton Parkway; and Exit 221, 104th Avenue. Photo taken 08/29/04.
This sign bridge, found in the high occupancy vehicle lanes, shows the connection from the freeway's managed lanes onto Colorado 224, U.S. 36, and Interstate 25/U.S. 87. This sign was installed at a point after August 2004. Photo taken 11/12/05.
The left two lanes become exit only for westbound U.S. 36/Denver-Boulder Turnpike to Boulder. This turnpike was originally a toll road built in 1952, and it traveled in a northwesterly direction to the southern city limits of Boulder. The connector between Interstate 25 and U.S. 36 designated as Colorado 382 until 1967, when the tolls were removed from the highway. At the time the turnpike and Colorado 382 were built, U.S. 87 was the sole designation for what is today Interstate 25, following an expressway alignment that bypassed Broadway (Colorado 53). Photo taken 08/29/04.
As a result of the toll removal in 1967, U.S. 36 was extended from the Denver civic center (intersection of Colfax Avenue and Broadway). First, U.S. 36 was rerouted out of downtown Denver and placed onto former Colorado 72 (Smith Road) and U.S. 6-85 (46th Avenue), which together formed what is today Interstate 70. By that time, Interstate 270 was complete (as of 1968 per the official map), so U.S. 36 followed a fairly convoluted routing: Interstate 70 west to Interstate 270 west to Interstate 76 west to Interstate 25 north to U.S. 36 west. Now that Interstate 270 is complete between Interstate 25 and Interstate 76 (as of 2002), U.S. 36 follows a continuous freeway corridor emanating from Interstate 70. Photo taken 08/29/04.
U.S. 36 west traffic departs from Interstate 25 at the left exit. U.S. 36 will remain a freeway as it passes through unincorporated Western Hills, the cities of Westminster and Broomfield, the city of Louisville, and unincorporated Superior. Then the freeway transitions onto 28th Street upon entering Boulder. The highway basically travels north-south through Boulder, then turns northwest again at Lyons, passing through the scenic Roosevelt National Forest before swiping U.S. 34 in Estes Park and ending at U.S. 34 in Rocky Mountain National Park. U.S. 36 offers the most direct route from Interstate 25 to Rocky Mountain National Park, assuming a high tolerance of Boulder traffic. Photo taken 08/29/04.
Northbound Interstate 25/U.S. 87 pass under the ramps and overpasses for U.S. 36 and Interstate 270. Photo taken 11/12/05.
The next exit along northbound Interstate 25/U.S. 87 is Exit 219, 84th Avenue. This exit serves south Thornton, Federal Heights, and Westminster. The city of Thornton was first developed in 1953 and incorporated as a city in 1956. The city was named after former Governor Dan Thornton and is home to 82,384 residents as of the 2000 Census. The 2004 population estimate indicates that Thornton has grown substantially, with an estimated 102,072 people living there only four years after the Census. Photo taken 08/31/04.
The right lane of northbound Interstate 25/U.S. 87 becomes exit only for Exit 219, 84th Avenue. To reach Interstate 76 east, use 84th Avenue east to Washington Street north to 88th Avenue east. Photo taken 08/31/04.
The next three exits along northbound Interstate 25 are Exit 219, 84th Avenue; Exit 220, Thornton Parkway; and Exit 221, 104th Avenue. Photo taken 08/31/04.
Interstate 25/U.S. 87 leave unincorporated Adams County and enter the city of Thornton just prior to the offramp to Thornton Parkway (Exit 219). Photo taken 08/31/04.
The next exit along northbound Interstate 25 is Exit 220, Thornton Parkway. This is one of the older bridges on Interstate 25 north of downtown Denver. Photo taken 08/31/04.
Northbound Interstate 25/U.S. 87 reaches the Thornton Parkway exit (Exit 220). This overpass is newer than the one shown in the previous photograph. Photo taken 08/31/04.
The next exit along northbound Interstate 25/U.S. 87 is Exit 221, 104th Avenue, one mile. The freeway now enters the city of Northglenn, the "Center of the Future." Northglenn was incorporated in April 1969, has a population of 34,006 people (2000 Census), and rests at an elevation of between 5160 and 5222 feet above sea level. This is one of the last major interchanges in the immediate Denver metropolitan area. Photo taken 02/02/02.
Northbound Interstate 25/U.S. 87 approaches Exit 221, 104th Avenue. The characteristic of Interstate 25 changes from urban to rural after it passes by 104th Avenue, but that distinction is changing as suburban sprawl extends further north. Northglenn is at the frontier of urban development trending northward along the Interstate 25 corridor, and it is likely that the urban expansion along Interstate 25 will continue northward from Northglenn. Photo taken 08/31/04.
Continuing north, the next exit along Interstate 25/U.S. 87 is Exit 223, Junction Colorado 128 and 120th Avenue. As noted on the sign, Colorado 128 extends west from this interchange via 120th Avenue toward U.S. 287. 120th Avenue extends east as a non-state facility. Photo taken 08/31/04.
The right lane becomes exit only for Colorado 128 (120th Avenue). The left three lanes continue north on Interstate 25 and unsigned U.S. 87. Photo taken 08/31/04.
Northbound Interstate 25 and U.S. 87 reach Exit 223, Junction Colorado 128 west and 120th Avenue east/west. Note that the exit only widens to two lanes, which allows for better traffic distribution at the top of the ramp. Photo taken 08/31/04.
The next exit along northbound Interstate 25 and U.S. 87 is Exit 225, 136th Avenue. A repaving project was underway at the time this photo was taken. Photo taken 08/31/04.
Northbound Interstate 25 and U.S. 87 reach Exit 225, 136th Avenue. This is a relatively new interchange that provides access to the rapidly developing areas of Broomfield to the west and Eastlake to the east. Photo taken 08/31/04.
When the 136th Avenue interchange was constructed, the city of Thornton beautified the overpass. Photo taken 11/12/05.
The next exit along northbound Interstate 25 and U.S. 87 is Exit 228, Junction E-470 east to Denver International Airport and Northwest Parkway west to Broomfield and Boulder. Interstate 25 and U.S. 87 leave Adams County and enter the city/county of Broomfield (most of the city is located southwest of Interstate 25 along the U.S. 36 and Northwest Parkway corridors, so most of the Interstate 25 corridor within Broomfield is not developed yet). Photo taken 08/31/04.
Northbound Interstate 25 and U.S. 87 reaches Exit 228, Junction E-470 and Northwest Parkway. This symmetrical stack interchange, which serves as the northern terminus of Toll E-470, was constructed between 2001 and 2003. E-470 extends east from here toward the airport, turning south to form an eastern bypass of the Denver metropolitan area and linking to Interstate 25 in Douglas County, south of Denver. At that interchange, Toll E-470 shifts into free Colorado 470 west to Morrison and Golden via Ken Caryl Ranch. Photo taken 08/31/04.
Here is a view of the transition ramp from northbound Interstate 25 to E-470 (right lane) and Northwest Parkway (left lane). To the west, the Northwest Parkway is most recent addition to the Denver beltway system. The parkway currently provides a toll connection between Interstate 25 and U.S. 36 via Broomfield city/county. Beyond Broomfield, plans call for a final link to Denver's belt system by connecting the Northwest Parkway with Colorado 470 in Golden by 2010. Photo taken 08/31/04.
This is a view of northbound Interstate 25 and U.S. 87 as the freeway passes under the E-470 and Northwest Parkway interchange complex. Broomfield grew from its original town center at the intersection of 120th Avenue (Colorado 128) and Wadsworth Boulevard (U.S. 287/Colorado 121), and it was incorporated as a city in 1961, eventually taking parts of four counties as it expanded in the subsequent years. In 2001, Broomfield seceded from the four counties and became its own county with 33.6 square miles. As of 2003, 42,169 people call Broomfield home. Photo taken 11/12/05.
Rewinding to 2002, this photo and the next photo show northbound Interstate 25/U.S. 87 as it approaches the then-under construction northern E-470 interchange. This is where E-470 and the Northwest Parkway tie into the Interstate 25 freeway. Note how the freeway is temporarily moved to the west (left) to allow for interchange construction. Interstate 25 will be straightened back out once the new interchange here is completed. Photos taken 02/02/02.
Another view of the Interstate 25/E-470 interchange construction looking east from northbound Interstate 25. This picture shows the construction of the Interstate 25 and E-470 interchange as seen from northbound Interstate 25 looking east at the future interchange. Photos taken 02/02/02.
The next exit along northbound Interstate 25/U.S. 87 is Exit 229, Junction Colorado 7. Interstate 25 narrows from six lanes to four lanes just north of the Colorado 7 interchange. The large power lines to the east (right) of the freeway are relatively new. Photo taken 08/31/04.
Use Colorado 7 east to Brighton, where it meets U.S. 85 and Interstate 76. To the west, Colorado 7 travels generally toward Estes Park, but it takes a much more angular route than U.S. 36. Photo taken 08/31/04.
Northbound Interstate 25 and U.S. 87 reaches Exit 229, Junction Colorado 7 west to Lafayette and east to Brighton. Photo taken 08/31/04.
Back in 2002, the first photo shows the point where six lanes used to narrow to four lanes along northbound Interstate 25. Interestingly, the left lane used to end, which forces faster moving traffic to merge into the middle lane. Oftentimes, the left lanes are preserved, and the right lanes are forced to merge with the middle lanes. Photos taken 02/02/02 and 11/12/05.
Now in 2004, the highway has been gradually upgraded to include a third lane in each direction. The next exit along northbound is Exit 232, Junction Weld County Route 8 to Erie and Dacono. Photo taken 08/31/04.
Northbound Interstate 25/U.S. 87 reaches Exit 232, Junction Weld County Route 8 to Erie and Dacono. Interstate 25 leaves Broomfield County and enters Weld County at Exit 232, Junction Weld County Route 8. Photo taken 08/31/04.
