Origin
Boulder, CO
Late night in Boulder on Tuesday
Local time
2:45 AM
MDT
Current temp
53°F
Unavailable
Live forecast
Trip from Boulder, CO to Thornton, CO
Pin this tripCompiled and reviewed by the US Trip Planner planning team at COD Solutions Oy · Last reviewed Apr 21, 2026 · Editorial standards
Drive Time
33m
Distance
21.7 mi
35 km
Drive Score
7/10
Good drive
Same Day?
Yes, doable
Fuel Cost
$3
one way
EV Charging
Unknown
Best Time to Leave
4 AM
0h 30m
★
6 AM
0h 33m
8 AM
0h 39m
10 AM
0h 35m
12 PM
0h 34m
3 PM
0h 35m
5 PM
0h 38m
8 PM
0h 31m
Estimated drive times based on typical traffic patterns. Actual times may vary with weather, construction, and real-time conditions.
Boulder, CO
Wikimedia Commons
Thornton, CO
Wikimedia Commons
Trip Overview
Boulder to Thornton is 21.7 miles and takes about 33 minutes via Denver–Boulder Turnpike, with a fuel budget near $3 and enough daylight to finish in a day. This short trip stays within Colorado's Mountain West region, making it a straightforward connection between two familiar areas. Given its brief duration, this drive is ideal for a quick commute or a simple hop between cities without requiring significant planning. You'll primarily be on a highway, so expect a direct and efficient journey. This route is best suited for those looking for a no-fuss drive with minimal time commitment.
Main Roads
| Road | Distance | Duration |
|---|---|---|
| Denver–Boulder Turnpike | 14.9 mi | 17m |
| West 92nd Avenue | 2.5 mi | 5m |
| Thornton Parkway | 2 mi | 4m |
| 28th Street | 0.8 mi | 1m |
| Arapahoe Avenue | 0.6 mi | 1m |
| Sheridan Boulevard | 0.3 mi | <1m |
| Dorothy Boulevard | 0.2 mi | <1m |
| 19th Street | <0.1 mi | <1m |
Longest stretch:
Denver–Boulder Turnpike
— 14.9 mi, about 17m
Turn-by-Turn Driving Directions
Step-by-step road directions between Boulder, CO and Thornton, CO.
1
Start on this road
87 ft
·
6 sec
·
this road
2
Turn right onto 19th Street
143 ft
·
13 sec
·
19th Street
3
Turn left onto Arapahoe Avenue
0.6 mi
·
1 min
·
Arapahoe Avenue
Use the left / straight / right lanes.
4
Turn right onto US 36
0.8 mi
·
1 min
·
28th Street
5
Turn straight onto US 36
3.4 mi
·
4 min
·
Denver–Boulder Turnpike
Use the straight / slight right lanes.
6
Keep slight right at fork onto US 36
1.7 mi
·
1 min
·
Denver–Boulder Turnpike
7
Keep slight right at fork onto US 36
2.6 mi
·
3 min
·
Denver–Boulder Turnpike
8
Keep slight right at fork onto US 36
2.4 mi
·
2 min
·
Denver–Boulder Turnpike
9
Keep slight right at fork onto US 36
2.2 mi
·
2 min
·
Denver–Boulder Turnpike
10
Keep slight right at fork onto US 36
1.9 mi
·
2 min
·
Denver–Boulder Turnpike
11
Keep slight right at fork onto US 36
0.8 mi
·
53 sec
·
Denver–Boulder Turnpike
12
Take the exit
0.3 mi
·
37 sec
Toward CO 95 South: Sheridan Boulevard
Use the slight right lane.
13
Turn sharp left onto CO 95
0.3 mi
·
39 sec
·
Sheridan Boulevard
Use the left lane.
14
Turn straight
306 ft
·
11 sec
15
Turn straight onto West 92nd Avenue
2.5 mi
·
5 min
·
West 92nd Avenue
Use the left / straight lanes.
16
Continue on Thornton Parkway
2.0 mi
·
4 min
·
Thornton Parkway
Use the straight / right lanes.
17
Turn right onto Dorothy Boulevard
0.2 mi
·
51 sec
·
Dorothy Boulevard
Use the right lane.
18
Turn right
116 ft
·
8 sec
19
Arrive at destination
Heads-up: tricky spots
5 of 155 decision points cluster between mile 0 and 21.7 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
6
0 mi into trip
|
~0m in
|
Arapahoe Avenue
Turn left onto Arapahoe Avenue
Lane positioning matters here
Use the left / straight / right lanes.
6
16.3 mi into trip
|
~20m in
Take the exit toward CO 95 South: Sheridan Boulevard
Exit ramp - move to the correct lane early. Lane positioning matters here
Use the slight right lane.
Toward CO 95 South: Sheridan Boulevard
5
16.6 mi into trip
|
~21m in
|
CO 95 / Sheridan Boulevard
Turn sharp left onto CO 95 / Sheridan Boulevard
Sharp turn - reduce speed on approach. Lane positioning matters here
Use the left lane.
6
21.5 mi into trip
|
~32m in
|
Dorothy Boulevard
Turn right onto Dorothy Boulevard
Lane positioning matters here
Use the right lane.
5
21.7 mi into trip
|
~32m in
Turn right
Navigation decision point
Fuel & Cost
Regular Gas
$3.27 one way
$6.54 round trip
$3.83/gal
25.4 MPG avg
8 kg CO2
| Fuel Type | $/gal | One Way | Round Trip |
|---|---|---|---|
| midgrade | $4.05 | $3.46 | $6.92 |
| premium | $4.39 | $3.75 | $7.51 |
| diesel | $5.61 | $4.79 | $9.58 |
Estimated Tolls: $1.04
Denver–Boulder Turnpike
(14.9 mi)
$1.04
Toll estimates based on average 2024-2025 rates. EZ-Pass/SunPass discounts may lower the actual cost.
Drive Cost (one way)
Fuel
$3
Tolls
$1
Total
$4
Estimated CO2 emission: 7.6 kg one way. Prices: EIA weekly data, 2026-04-13.
Driving Electric?
About $2 in charging · 0 stops · 63% less CO2
| Vehicle Type | kWh | Stops | DC Fast | Home Charge |
|---|---|---|---|---|
| Average EV | 6.5 | 0 | $2.28 | $1.04 |
| Efficient EV | 5.4 | 0 | $1.90 | $0.87 |
| EV Truck/SUV | 8.7 | 0 | $3.04 | $1.39 |
Gas CO2
8 kg
EV CO2
3 kg (63% less)
This trip is well within single-charge range for most EVs. No charging stops needed if you start fully charged.
DC fast charging avg $0.35/kWh. Home charging avg $0.16/kWh. US grid CO2: 0.39 kg/kWh.
Travel Intel
Current conditions at both ends of the drive.
Destination
Thornton, CO
Late night in Thornton on Tuesday
Local time
2:45 AM
MDT
Current temp
36°F
Unavailable
Live forecast
Time zone
Same local time
Origin and destination are on the same clock, so arrival timing is easier to judge at a glance.
Temperature spread
17 degrees cooler at arrival
A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.
Road read
33m on the road
Use the two city cards together: check the sky where you start, then compare it with the local time and temperature at arrival.
Weather data from the National Weather Service. Conditions may change; check closer to your travel date.
What kind of drive is this?
This is a highway-focused drive, with 78% of the route utilizing major roadways. The longest uninterrupted stretch you'll encounter is 14.9 miles along the Denver–Boulder Turnpike. As you transition from the Denver–Boulder Turnpike onto West 92nd Avenue and then Thornton Parkway, the character shifts slightly from pure highway to more suburban arterial roads. While primarily highway, the final segments offer a glimpse of local development before reaching your destination. The overall feel is one of efficient travel on well-maintained roads.
78% highway — fuel and pacing are the main things to plan.
19 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 14.9 mi on Denver–Boulder Turnpike.
How Hard Is This Drive?
9/10
This is a straightforward highway drive that stays mostly on Denver–Boulder Turnpike and West 92nd Avenue. This route has several spots where lane changes, forks, or exits need your full attention. The trickiest moment comes early in the drive near Arapahoe Avenue.
Driving Effort
9/10
Focused - lots of decisions in a short distance, but it is over quickly
Balances navigation complexity with total wheel time.
This is a short but busy drive. With 15 decision points packed into just 21.7 miles, you will need to pay attention to lane changes and exits — but the whole thing is over in 33m.
Where does it get tricky?
The main spots that need attention: near the start (Arapahoe Avenue): Lane positioning matters here; at 16.3 miles: Exit ramp - move to the correct lane early. Lane positioning matters here; at 16.6 miles (CO 95 / Sheridan Boulevard): Sharp turn - reduce speed on approach. Lane positioning matters here.
Who Is This Route For?
Weekend Trip
Doable as a same-day drive at 33m. Total distance: 21.7 miles.
Family Friendly
Moderate complexity with 0 natural rest stops along the way.
Solo Traveler
33m drive, comfortable solo distance.
EV Driver
0 DC fast chargers along the route. Coverage: unknown.
First-Time Driver
Mostly highway driving (78%). Some complex stretches to watch for.
Frequently Asked Questions
The longest stretch is about 14.9 miles on Denver–Boulder Turnpike. The full list of main roads is in the Roads section above.
Expect about $1.04 in tolls one way, starting with Denver–Boulder Turnpike. Most Northeast and Midwest toll agencies accept E-ZPass; in the West and Texas, transponders like TxTag or FasTrak apply. If you do not have a transponder, cashless tolling plates will mail a bill to the vehicle's registered address — usually with a surcharge, so a rental-car toll pass is often cheaper than paying by mail.
It helps. This route has a higher-than-average number of complex decision points, which get harder in the dark. If the last hour of the trip is on surface roads or mountain grades, aim to arrive at Thornton, CO before sunset when you can. Check the Trip Plan for departure windows that land you in daylight.
Yes. At under 2 hours behind the wheel, this works well for families — plan one quick stop if you have younger kids.
The main spots that need attention: near the start (Arapahoe Avenue): Lane positioning matters here; at 16.3 miles: Exit ramp - move to the correct lane early. Lane positioning matters here; at 16.6 miles (CO 95 / Sheridan Boulevard): Sharp turn - reduce speed on approach. Lane positioning matters here.
Yes. A round trip is manageable in a single day if you plan a break at Thornton, CO before heading back.
How this page is built
Compiled by the US Trip Planner planning team at COD Solutions Oy from open government datasets — OSRM over OpenStreetMap for geometry, and EIA for fuel prices. See our methodology for refresh cadence and limitations.
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