LOS ANGELES, CA—The Lone-Paiute Shoshone Tribe of California is seeking protections for a recently discovered massacre site.

Some 35 Paiutes were killed by U.S. soldiers and local ranchers on March 19, 1863. The site, which includes bullets and tribal artifacts, was unearthed in 2009 as part of work for an air pollution control project.

“This ground, and the artifacts in it, is who we are,” Kathy Jefferson Bancroft, the tribe’s historic preservation officer, told The Los Angeles Times.

The tribe wants to ensure the site is not harmed as part of the pollution control project. The...