Old Monroe is a small town located in Lincoln County, Missouri. The region experiences a humid continental climate, characterized by hot summers and cold winters. Summers are typically warm and humid, with temperatures often reaching the mid-80s (Fahrenheit), while winters are cold, with temperatures dropping below freezing.

Hydrologically, Old Monroe is situated near the Mississippi River, which provides recreational opportunities like fishing and boating. The river also influences the town's hydrology, acting as a water source and affecting the local climate. Additionally, there are several small creeks and streams in the area.

Outdoor enthusiasts can enjoy various recreational activities in Old Monroe, including hiking, camping, and hunting. The town is surrounded by picturesque landscapes and offers access to nearby parks and natural areas, making it an ideal destination for nature lovers. Whether exploring local trails or enjoying water-based activities, Old Monroe provides ample opportunities to experience the beauty of the outdoors.