Lambert was a station on the Great Northern branch line of Sidney. Lambert is located near Fox Lake and Fox Creek. For that reason, the post office was originally known as Fox Lake. The Lambert office was established in 1914 with Edmund Bronson as postmaster. (from Cheney's Names on the Face of Montana, Mountain Press Publishing Company)
Lambert is located near the confluence of the Yellowstone and Missouri rivers near a 75-mile-long irrigated valley. Oil and agriculture are the prominent industries and crops include grains, sugar beets, corn, beans and hay. Located in the Williston Oil Basin, oil pumping and exploration can be found throughout the area. On August 12, 1806, Lewis and Clark again were at the joining of the two rivers on their way back east. This was their meeting point. On their way back from the west coast, when they entered what would become Montana, Lewis followed the Missouri River and Clark explored the Yellowstone.
The nearby town of Sidney is home to the Mon-Dak Heritage Center, which features area history and includes an extensive street scene of the early 1900s. Northeast of Lambert is the Fort Union Trading Post, a National Historic Site, which sits astride the Montana/North Dakota state line. The original fort built in 1828 by the American Fur Company.