Having separated geographically from Schuyler County in 1839, Mt. Sterling became the seat of government for the County of Brown. However, the village was not officially organized until 1854 with the Courthouse being constructed in 1868. Mt. Sterling, located geographically in the center of the county, quickly became the hub of economic and civic activity during the 19th and 20th centuries. The advent of the railroad era fostered the town's prominence in the county. The Wabash Depot and freight house, also built in 1868, quickly became a focal point of activity and interest for the citizens of the County.

Upon stepping on the depot platform, one cannot help but think of the people who arrived and departed through the doors of the vintage depot. If one is imaginative, he or she can hear the approach of the train and mentally watch those who arrive or depart. The old depot observed thousands of joyous and sad arrivals and departures. It witnessed boys leaving for war; it absorbed the sorrow of those families returning for funerals or perhaps those who left, never to return, but it also witnessed joyous homecomings. There were two passenger trains each way every day and one freight train each way. Children and other folks crowded around as the circus train arrived; onlookers came to see entertainers on their way to the Opera House. Coal and lumber arrived to fuel the homes and business and to build new structures. Merchants were much relieved when their latest delivery of goods from the east coast arrived and could be transported to the busy uptown area. Today that old depot, carefully restored by the Brown County Historical Society, sits on the Fairgrounds and houses artifacts that tell the story of Mt. Sterling and its environs. It is known as the Whistle Stop Depot Museum. Nearby is the restored one room school, Ferguson, which displays artifacts from country schools. The Fairgrounds, upon which these buildings are housed, had its origins in 1872 when a group of enterprising men bought a patch timber on the northeast corner of the city and organized an agricultural society. Thus began, what is today, the longest continuously running county Fair in the State of Illinois.