The purpose of this legislation is to amend an existing law to withdraw and reserve specific public lands near the Yuma Proving Ground in Arizona for military use. This is intended to support military readiness and security. The key provisions of this legislation include the withdrawal of approximately 21,782 acres of federal land and an additional 249 acres for military purposes. This means that these lands will no longer be available for public entry, mining, or other uses under public land laws.