Is there a train from Longmont to Thornton?

No, there is currently no direct passenger rail service between these two cities.

How long is the drive?

The drive typically takes 40 to 55 minutes depending on traffic.

Are there tolls on this route?

I-25 is free, but E-470 is a toll road that can be used as an alternative.

What is the best time to leave?

Leaving before 6:30 AM or after 9:00 AM avoids the worst morning rush.

Does RTD serve Longmont?

Yes, RTD provides regional bus service connecting Longmont to the Denver metro area.

Longmont

Thornton

Bus Driving

Longmont to Thornton

Updated: 01 Jun 2026

The journey from Longmont to Thornton covers approximately 30 miles along the I-25 corridor. Most commuters utilize personal vehicles, taking advantage of the direct highway access. Travel time typically ranges from 40 to 55 minutes depending on peak-hour congestion near the E-470 interchange. Public transit options include the RTD bus service, which connects the two cities via regional routes. This route is a primary artery for residents moving between Boulder County and the northern Denver suburbs.

Total Distance: 48 km driving distance; 42 km straight-line air distance.

Fastest Way

Driving via I-25 South takes approximately 40 minutes during off-peak hours.

Cheapest Way

RTD Bus, costing $3 for a local fare, is the most economical choice for daily commuters.

Compare Longmont to Thornton Routes

	Bus Connecting	Driving Direct
Duration	1 hour 20 mins	45 mins
Avg Price	$3 - $6	$8 - $12 in fuel
Operator	RTD Denver	Personal Vehicle
Route	Route 324 to regional connections.	I-25 South to exit 221 or 223.
Tip	Use the RTD mobile app to track real-time bus arrivals at the Longmont Park-n-Ride.	Avoid I-25 during 7:00 AM and 5:00 PM to bypass heavy construction zones.

Travel Tips

Check Traffic
Use the CDOT Cotrip website to monitor I-25 accidents before leaving.
Park-n-Ride
Utilize the Longmont Park-n-Ride to avoid parking fees in Thornton.
Weather Prep
Keep an ice scraper in your car, as Colorado weather changes rapidly.
Toll Roads
Consider using E-470 if I-25 is heavily congested, though tolls apply.
Bus Passes
Purchase a monthly RTD pass if you commute more than three times weekly.

Safety Tips

Winter Driving
Ensure your tires have adequate tread for sudden snowstorms on I-25.
Emergency Kit
Carry a blanket and water in your vehicle during winter months.
High-Speed Traffic
Maintain a safe following distance as speeds on I-25 often exceed 70 mph.
Sun Glare
Wear polarized sunglasses, especially during sunrise and sunset commutes.