What is on the Back of a Quarter?

By GovMint :

The back, or reverse, or U.S. Quarters feature a variety of designs depending upon the current series being issued. For Example, the 50 State Quarters Program which ran from 1999 to 2008 featured reverse designs that celebrated each state's unique heritage and symbols. The next quarter series showcased reverse designs that honored the many United States National Parks. Known as the America the Beautiful Quarters program, this series ran from 2010 to 2021. 

Meanwhile, the reverse designs of the subsequent and still on-going American Women Quarters Program, which began in 2022, celebrate notable women in American history.  Before these long -standing series, the reverse of the quarter was adorned with a heraldic eagle design which was used from 1932 to 1998.

Sources Used:

https://www.usmint.gov/coins/coin-medal-programs/circulating-coins/quarter