Lamar to Thornton is 209.2 miles and takes about 4 hours via US 287 and Dwight D. Eisenhower Highway, with a fuel budget near $34 and enough daylight to finish in a day. This trip stays within Colorado, moving from the Mountain West region to another part of the Mountain West. Expect a mix of highway cruising and surface roads as you make your way across the state. It's a straightforward drive, suitable for a single day's travel, with a moderate fuel cost.
Trip Pace
Same-day drive is realistic
A same-day return is possible, but it will make for a full day on the road.
Break Rhythm
1 planned break
Plan on a short reset every 3 to 4 hours to stay fresh behind the wheel.
Midpoint
104.6 miles from Lamar, CO
A natural place for your longest stop of the day
, about 2h 5m into the drive
.
Main Roads
Road
Distance
Duration
US 287
108 mi
2h 7m
Dwight D. Eisenhower Highway
83.1 mi
1h 25m
Tuskegee Airmen Memorial Highway
6.2 mi
7m
US 50
5.7 mi
7m
North Valley Highway
2.1 mi
2m
South Main Street
1.8 mi
3m
Thornton Parkway
0.9 mi
1m
Dorothy Boulevard
0.2 mi
<1m
Longest stretch:
US 287
— 108 mi, about 2h 7m
Traffic on I-70
Hour-of-day weekday pattern from 12 FHWA count stations on your route.
Peak
7 AM
~3,803 veh/hr typical
· worst 4,757
Quietest
2 AM
~394 veh/hr
Peak-to-quiet ratio
9.7×
busier at peak than in the quiet hours
12a6anoon6p11p
Averaged across 52 weeks of 2023 FHWA Travel Monitoring Analysis System data. Weekday hours only (Mon–Fri).
Turn-by-Turn Driving Directions
Step-by-step road directions between Lamar, CO and Thornton, CO.
1
Start on West Elm Street
436 ft·21 sec·West Elm Street
2
Turn left onto US 287; US 385
1.8 mi·3 min·South Main Street
Use the straight / right lanes.
3
Continue on US 50; US 287
5.7 mi·7 min·US 50; US 287
Use the straight lane.
4
Take the exit onto US 287
0.4 mi·32 sec·US 287
Toward US 287 North: LimonUse the slight right lane.
5
Keep slight right at fork onto US 287
108 mi·2 hr 6 min·US 287
Toward US 287 North: LimonUse the straight lane.
6
Turn left
0.3 mi·39 sec
Toward I 70 West: Denver
7
Merge onto I 70
77 mi·1 hr 16 min·Dwight D. Eisenhower Highway
Use the straight lane.
8
Continue on I 70
3.4 mi·4 min·Tuskegee Airmen Memorial Highway
Use the straight / slight right lanes.
9
Keep slight right at fork onto I 70
2.8 mi·3 min·Tuskegee Airmen Memorial Highway
Use the straight lane.
10
Keep slight right at fork onto I 270
6.6 mi·8 min·Dwight D. Eisenhower Highway
Exit 279AToward I 270 West: BoulderUse the straight / slight right lanes.
11
Take the exit
0.3 mi·41 sec
Toward I 25 North: Fort CollinsUse the slight right lane.
12
Merge onto I 25
0.8 mi·1 min·North Valley Highway
13
Keep slight right at fork onto I 25
1.3 mi·1 min·North Valley Highway
Use the slight right lane.
14
Take the exit
0.4 mi·43 sec
Exit 220Toward Thornton ParkwayUse the slight right lane.
15
Turn right onto Thornton Parkway
0.9 mi·1 min·Thornton Parkway
Use the left / straight / right lanes.
16
Turn right onto Dorothy Boulevard
0.2 mi·51 sec·Dorothy Boulevard
Use the right lane.
17
Turn right
116 ft·8 sec
18
Arrive at destination
Trip Plan
Given the 4-hour drive time, leaving Lamar in the morning allows you to reach Thornton well before evening. This route is designed for a single day, so you have the flexibility to stop for a break if needed, but with only one recommended stop, it's easily manageable. Keep an eye on your fuel, as the estimated cost is $34, and plan your last fuel stop before hitting the more urban areas around Thornton. A practical tip for this drive is to be aware of the 108-mile stretch on US 287; ensure you're comfortable with that segment before setting off.
Morning Departure
An early start around 7-8 AM gets you there with plenty of daylight left.
Evening Departure
A late afternoon start means arriving after dark. Morning is better.
You can normally do this drive in one day.
Plan roughly 1 meaningful break for fuel, food, and rest.
The halfway point lands around 104.6 miles from Lamar, CO, or about 2h 5m into the drive.
The longest continuous stretch on this route runs about 108 miles.
This is a comfortable same-day trip.
Departure
Before you leave
Start with fuel, water, and navigation already sorted so the first hour feels easy.
First stop
Around 46 miles or 56m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 104.6 miles or 2h 5m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Final approach
Final hour starts around 3h 15m
Traffic, exits, and arrival timing usually matter more near Thornton, CO than in the middle of the route.
Before You Leave
+
Open the route before leaving Lamar, CO so your first major turns are already loaded.
+
Leave with enough water and a charging cable within reach, not packed away.
+
Check your fuel range against the first long segment, especially if you are starting outside city service areas.
Day 1
Settle into the route from Lamar, CO
This is one driving day of about 209.2 miles and 4h.
Your first comfortable stop window is around 46 miles from Lamar, CO.
This route can stay practical as a one-day drive if traffic stays reasonable.
Plan about 1 real break rather than only quick fuel stops.
The longest stretch is on US 287 for about 108 miles.
Where to Stop
Rest stops, refuel points, and overnight suggestions along this route.
Place data sourced from public business listings. Hours and availability may vary.
Heads-up: tricky spots
5 of 14
5 decision points cluster between mile 7.6 and 207.6 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
6
7.6 mi into trip|~11m in|US 287
Take the exit onto US 287 toward US 287 North: Limon
Exit ramp - move to the correct lane early. Lane positioning matters here
Use the slight right lane.
Toward US 287 North: Limon
7
7.9 mi into trip|~11m in|US 287
Keep slight right at fork onto US 287 toward US 287 North: Limon
Highway fork - watch signs carefully. Lane positioning matters here
Use the straight lane.
Toward US 287 North: Limon
6
195.8 mi into trip|~3h 40m in|I 70 / Tuskegee Airmen Memorial Highway
Keep slight right at fork onto I 70 / Tuskegee Airmen Memorial Highway
Highway fork - watch signs carefully. Lane positioning matters here
Use the straight lane.
8
198.6 mi into trip|~3h 43m in|I 270 / Dwight D. Eisenhower Highway
Keep slight right at fork onto I 270 / Dwight D. Eisenhower Highway toward I 270 West: Boulder
Highway fork - watch signs carefully. Lane positioning matters here
Use the straight / slight right lanes.
Exit 279A
Toward I 270 West: Boulder
7
207.6 mi into trip|~3h 56m in
Take the exit toward Thornton Parkway
Exit ramp - move to the correct lane early. Lane positioning matters here
Use the slight right lane.
Exit 220
Toward Thornton Parkway
Fuel & Cost
Regular Gas
$31.90 one way
$63.80 round trip
$3.87/gal25.4 MPG avg73 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.12
$33.91
$67.82
premium
$4.45
$36.68
$73.35
diesel
$4.80
$39.50
$79.00
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$32
Meals
$25–$50
Total
$57–$82
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 73.2 kg one way.
Prices: EIA weekly data, 2026-07-13.
Driving Electric?
About $22 in charging
· 0 stops
· 67% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
62.8
0
$21.97
$10.04
Efficient EV
52.3
0
$18.31
$8.37
EV Truck/SUV
83.7
1
$29.29
$13.39
Gas CO2
73 kg
EV CO2
24 kg (67% 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.
Forecast as of Jul 19, 2026
Origin
Lamar, CO
Late night
in Lamar on Sunday
Local time
5:03 AM
MDT
Current temp
64°F
Mostly Clear
ESE 0 to 15 mph5% chanceLive forecast
Heat Advisory
Heat Advisory issued July 18 at 4:46AM MDT until July 20 at 9:00PM MDT by NWS Denver CO
Destination
Thornton, CO
Late night
in Thornton on Sunday
Local time
5:03 AM
MDT
Current temp
67°F
Mostly Clear
SE 3 to 10 mph2% chanceLive forecast
Heat Advisory
Heat Advisory issued July 18 at 4:46AM MDT until July 20 at 9:00PM MDT by NWS Denver CO
57°F
Limon, CO
105 mi in
Seasonal Notes
Summer travel usually means heavier construction, hotter rest stops, and busier weekend traffic around major cities.
Winter travel shortens daylight, so a route that looks manageable on paper can feel much longer after dark.
Holiday weekends tend to make both departure and arrival windows slower than the raw route time suggests.
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
3 degrees warmer at arrival
A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.
Road read
4h on the road
An early start around 7-8 AM gets you there with plenty of daylight left.
Weather data from the National Weather Service. Conditions may change; check closer to your travel date.
More Details
What kind of drive is this?
You'll spend about 55% of this 209.2-mile drive on highways. The longest continuous stretch on a highway is 108 miles on US 287. After that, the profile shifts to mixed highway and surface roads, meaning you'll transition from faster, limited-access driving to roads with more local traffic and intersections. Be prepared for a change in pace as you move between these two types of road.
55% highway, the rest on surface roads — varied driving throughout.
18 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 108 mi on US 287.
How Hard Is This Drive?
9/10
This route mixes highway mileage with some local-road sections near the start or finish. This route has several spots where lane changes, forks, or exits need your full attention. The trickiest moment comes around 7.6 miles in near US 287.
Driving Effort9/10
High effort - long or complex enough to need steady focus all day
Balances navigation complexity with total wheel time.
This is a demanding drive. With 14 significant decision points across 209.2 miles, you will need to stay alert - especially through interchange areas and urban stretches. Consider splitting it into segments if you are not comfortable with fast highway navigation.
Where does it get tricky?
The main spots that need attention: at 7.6 miles (US 287): Exit ramp - move to the correct lane early. Lane positioning matters here; at 7.9 miles (US 287): Highway fork - watch signs carefully. Lane positioning matters here; at 195.8 miles (I 70 / Tuskegee Airmen Memorial Highway): Highway fork - watch signs carefully. Lane positioning matters here.
Thornton is a city of about 144,000 in the Denver Metropolitan Area of the western U.S. state of Colorado. The city lies northwest of Denver in Adams and Weld counties. It is a diverse community with a strong commitment to quality of life and environmental issues.
Doable as a same-day drive at 4h. Total distance: 209.2 miles.
Family Friendly
Moderate complexity with 1 natural rest stops along the way.
Solo Traveler
4h drive, comfortable solo distance.
Frequently Asked Questions
The longest stretch is about 108 miles on US 287. The full list of main roads is in the Roads section above.
Yes — we found about 12 rest areas or service plazas within a short detour of the route (from OpenStreetMap). See the Rest Stops tab under Nearby Places for locations and mile markers. Plan to stretch, use the bathroom, and top off fluids every 2–3 hours on longer drives.
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.
Only with planning. This is a long drive for kids — consider splitting it into two days rather than pushing through. Plan at least 1 meaningful breaks. There are 12 rest areas along the route for bathroom stops.
The main spots that need attention: at 7.6 miles (US 287): Exit ramp - move to the correct lane early. Lane positioning matters here; at 7.9 miles (US 287): Highway fork - watch signs carefully. Lane positioning matters here; at 195.8 miles (I 70 / Tuskegee Airmen Memorial Highway): Highway fork - watch signs carefully. Lane positioning matters here.
Possible but tiring. At 4.0 hours each way, an in-and-out day trip would put you behind the wheel for 8.0 hours — manageable with a long break at Thornton, CO, but most travelers stay overnight.
