Petersburg is located on the north end of Mitkof Island in the center of the Inside Passage of Southeast Alaska. It is located approximately 110 miles north of Ketchikan and 120 miles south of Juneau. Mitkof Island is wedge-shaped, approximately 24 miles long and 15 miles wide at the widest part, with an area of about 200 square miles. It is located very close to the geographic center of the Alexander Archipelago which makes up Southeast Alaska

Like most of Southeast, Mitkof Island is mountainous and heavily forested. The island's highest point is Crystal Mountain (3317 ft.), with other peaks around 2500 feet. The vegetation consists of muskeg, a spongy, mossy bog which always stays wet, and numerous trees and shrubs within the temperate rainforest.

The high, rugged mountains of the Alaska Coast Range, which is known for its spectacular fjords, icefields, and tidewater glaciers, are on the mainland, just a few miles east of Petersburg, across Frederick Sound. Petersburg is the a jumping-off point for serious climbers of Devil's Thumb's 9000 foot rock face. Devil's Thumb is a prominent landmark, visible on a clear day from most of Petersburg.

Wrangell Narrows, 20 miles of narrow tidal waterway, separates Mitkof Island from its close neighbor Kupreanof Island. In some areas Wrangell Narrows is barely wide enough to accommodate the Alaska State ferries and does not allow for the passage of larger cruise ships. The "Narrows" is famous for it many navigational markers. With tides that can range from a high of 19 feet to a low of -4 feet in one day, the water often rushes through the Wrangell Narrows adding to the navigational challenges.

The Wrangell Narrows meets Frederick Sound near Petersburg. Frederick Sound is the major Southeast waterway connecting Stephans Passage and Chatham Strait. The rich waters of Frederick Sound are home to vigorous runs of salmon, deep dwelling halibut, and are a prime summer feeding area for humpback whales.

Petersburg is the gateway to nearby Stikine-LeConte and Petersburg Creek-Duncan Salt Chuck Wilderness Areas.

Information on timber harvest, wildlife & fisheries
management, recreation, minerals and more.
http://www.fs.fed.us/r10/tongass/

USFS info on the Stikine Icefield
http://www.fs.fed.us/r10/tongass/forest_facts/
resources/geology/stikineicefi elds.htm