Early in 1843 the U.S. War Department built the government House and established a federal land agency on Porter's Island - The small narrow island lying just off shore. Prospectors found small deposits of Copper, Ore and Native Copper in the cliffs and on the ridges of the surrounding hills. The first copper claims recorded in Michigan under Federal Law were located here in 1843.

A rush followed which reached its peak in 1848. Hundreds of claims were located and explored. Copper Harbor was a boom town with stores, hotels and saloons. Those were the days of whiskey and whiskers. One of the earliest newspapers in Michigan started publication here in 1846 as the Lake Superior News and Mining Journal with headquarters at the Astor House.