Willis is a city in Montgomery County, Texas, United States, located eight miles north of Conroe in north central Montgomery County. The city began to develop in 1870 after what is now a Union Pacific Railroad was built through the area. As a part of the Piney Woods, The Willis economy has historically been driven by lumber, agriculture, and the manufacture of lumber and agriculture equipment. As of 2010, the population of Willis was to be 5,662. In 2008, after Willis' population passed 5,000, the city established a home rule city charter.