Port Costa is a small, unincorporated community located in Contra Costa County, California. Situated along the banks of the Carquinez Strait, it was once a bustling shipping port in the late 19th century, primarily serving the Southern Pacific Railroad. Today, it retains a quaint charm with historic buildings and a close-knit population. The area is known for its scenic views and outdoor activities, including hiking and birdwatching. Port Costa is also home to the Port Costa Conservation Society, which works to preserve the natural beauty and historical significance of the region. The community offers a peaceful retreat from urban life.