FHWA, on behalf of the Arizona Department of Transportation (ADOT), has issued a Notice of Intent to prepare a Tier 2 EIS for the Sonoran Corridor (State Route 410), a new high-capacity highway connecting Interstate 19 and Interstate 10 in Pima County, Arizona. The Tier 1 Final EIS and Record of Decision were completed in October 2021.1 Three preliminary build alternatives (A, B, and C) are under evaluation, each roughly 20.4 to 20.5 miles long within a 400-foot-wide alignment, plus a No Build Alternative. Resources to be analyzed include cultural and historic resources, biological resources, waters of the US, noise, and farmlands. Comments are due July 18, 2025.2