NORTHCLIFF, TEXAS. Northcliff is a residential community located just east of Interstate 35 about nine miles southwest of New Braunfels and seventeen miles west of Seguin in western Guadalupe County near the Comal County border. Development of the area had begun in the 1970s and included the construction of a country club and golf course. In 1990 the population was 1,800. It increased slightly to 1,819 in 2000. Northcliff is served by its own volunteer fire department.