Distance From Duncan Airport to St Louis Lambert International Airport

The distance from Duncan Airport () to St Louis Lambert International Airport (STL) is 1228 miles or 1975 kilometers or 1066 nautical miles.

The distance shown below is direct flight distance between airports. Straight-line distance does not account for the surface between the two points. It is the distance a bird or airplane would travel between the two points when flying above the surface. The straight line distance is the direct route between two points, regardless of whether or not there are roads that connect them.

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How long does it take to travel from Helena ( United States ) to St Louis ( United States )?

A one-way nonstop (direct) flight between Helena and St Louis takes around 2 hours 49 minutes.

Estimated flight time from Duncan Airport, Helena, United States to St Louis Lambert International Airport, St Louis, United States is 2 hours 49 minutes under avarage conditions. Your actual flying time may vary depending on wind direction/speed or weather conditions. This calculation does not include the departure and landing times of the aircraft. In addition, it does not cover the person identity check, ticket check-in and baggage collection times at the airport.

Travel Distance Between the Airports • - STL

Kilometers		1975 km
Statute Miles		1228 miles
Nautical Miles		1066 nm
Avg. Time of Flight		2 hours 49 minutes

Duncan Airport to St Louis Lambert International Airport Flight Route Map - to STL Flight Path

Location of Duncan Airport & St Louis Lambert International Airport is given below.
Click the map to view Helena to St Louis nonstop flight path and travel direction.

Click to see flight route on Google Map between Helena, United States and St Louis, United States. .

Nonstop flight route between Helena, United States and St Louis, United States.

Time Difference Between the Airports • - STL

Time difference between Helena (United States) and St Louis (United States) is 2 Hours.
St Louis time is 2 Hours ahead of Helena.

Location	Local Time
Helena (United States)	2026-03-20, 12:43:05 MDT
St Louis (United States)	2026-03-20, 14:43:05 EDT

Why should you arrive 3 hours before international flight? Flyers who are traveling to an international destination should arrive at the airport earlier than domestic flyers. This is because international flights can have additional check-in requirements, like passport verification, that need to be completed before you receive your boarding pass.

Origin

Duncan Airport ( / MT06) Helena, United States

Destination

St Louis Lambert International Airport (STL / KSTL) St Louis, United States