With a population of just over 30,000, Rexburg is one of the fastest growing cities in Idaho. With 49.6% of the population between the ages of 20 and 45, and the distinction of having the lowest median age (23.3) in the nation, Rexburg is a young and vibrant community. Rexburg is the county seat of Madison County.

Madison County's population increased 32% between 2002 and 2012, primarily because of the 2004 conversion of Ricks College (a two year junior college) to Brigham Young University-Idaho. BYU-Idaho continues to experience high enrollment rates, driving economic growth within Rexburg and Madison County. BYU-Idaho has plans to further expand its student population through 2015.

Rexburg has grown over 60% since the 2000 census, increasing from 17,000 to just over 30,000 in twelve years. The county too has experienced tremendous growth since 2002, increasing by almost 9,000; a quarter of that growth occurring between 2003 and 2004. As a whole, Rexburg ranks 10th in the state in population, and Madison County is the 4th fastest growing county in Idaho.