Rugged terrain and difficulty transporting equipment across the San Francisco Bay complicated efforts Monday to corral a wildfire on Angel Island.

The blaze, which started around 9 p.m. Sunday, had grown to 250 acres by Monday morning, Marin County fire officials said. It was 20 percent contained.

Click here for photos.

Smoke spread across the bay and the smell of flames permeated surrounding communities.

About 30 or 40 campers were evacuated from the island, a state park. There have been no injuries.

The 740-acre island is the largest in San Francisco Bay and is home to many historic buildings, including an immigration station that was the first stop for many people coming to the U.S. in the early 1900s.

"This side of the island has some of the most historic buildings," said James Dexter, a state parks employee who was stationed on the island. Dexter said the World War I-era Fort McDowell was also on that side of the island.

Fire crews from Marin County and San Francisco were dispatched to the island by boat, as well as firefighters from the U.S. Coast Guard. Two air tankers were also planned.

The fire was burning on the island's highest point, Mount Livermore, which is 781 feet above sea level.

The cause of the fire is under investigation.