Government Island is a 1,760-acre (7 km 2) island in the Columbia River north of Portland, in Multnomah County, in the U.S. state of Oregon.Though Interstate 205 passes over it on the Glenn L. Jackson Memorial Bridge, access to the island is only by boat.Although there is a city controlled locked gate in the 205 fence.) Government Island is known for its great blue heron colony and the Government Island State Recreation Area (primitive camping, beaches).