| State: | CA |
| Type: | SR |
| Route: | 221 |
| Section: | 521 |
| Maint: | Caltrans |
| Map Notes: | SR 221 highlighted in red |
| Alternate Name: | Napa-Vallejo Highway |
| Length Mi: | 2.682 |
| Length Round: | 3 |
| Direction A: | South |
| Terminus A: | near Napa |
| Direction B: | North |
| Terminus B: | in Napa |
| Counties: | Napa |
| Previous Type: | SR |
| Previous Route: | 220 |
| Next Type: | SR |
| Next Route: | 222 |
State Route 221 (SR 221) is a state highway in the U.S. state of California that runs in and just outside the City of Napa, providing access to Napa Valley College and Napa State Hospital. The highway's southern terminus is with State Route 12 and State Route 29 outside the southeast corner of the city, and its northern terminus is at State Route 121 inside the city. SR 221 forms part of the Napa-Vallejo Highway with SR 29.
Route 221 is the northernmost part of the Napa-Vallejo Highway. It is a divided four-lane expressway that serves as an alternate to the nearby Route 29 freeway into Napa from the south. Unlike Route 29, however, 221 provides direct access to Napa Valley College and Napa State Hospital. The southern terminus is with Route 29 (which also carries Route 12), where it continues as the Napa-Vallejo Highway. The northern terminus is an intersection with Route 121, where 121 continues north as Soscol Avenue.
SR 221 is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.
At SR 221's southern terminus with SR 12 / SR 29 and Soscol Ferry Road, the signalized intersection is being reconstructed into a double roundabout interchange to relieve congestion. However, the connection from westbound SR 12 / northbound SR 29 to Soscol Ferry Road will be eliminated. It is scheduled to open in the fall of 2024, with construction scheduled to be completed in 2025.[1]