Ennis, Texas is located in the northeastern part of the state and has a humid subtropical climate with hot summers and mild winters. The area is known for its rich soil and is a popular center for agriculture, particularly in the production of cotton. The Trinity River runs through the area, and hydrology constituents such as nitrates and phosphorus can be a concern for water quality. Outdoor recreation opportunities in Ennis include fishing and boating on the Trinity River, hiking and camping at nearby state parks, and visiting the Bluebonnet Trail in the spring when the state flower is in bloom. The city also hosts the National Polka Festival annually, which draws visitors from all over the country.