Nicomen Island is an island in the Fraser River east of Mission and between Deroche (E) and Dewdney (W). Located on the river's north side, and separated from the foot of the Douglas Ranges by Nicomen Slough, the island is near-totally given over to agriculture and constitutes a rural community in its own right, although "downtown Dewdney" is located near its western end and the Indian Reserve of the Lakahahmen First Nation is located about mid-way along its north side.
Settlement by non-natives began in 1861 with homesteading by a James Codville, who built a store and hotel and provided wintering quarters for animals belonging to miners of the Cariboo Gold Rush. In 1895 a large 300-acre farm was established by Sam MacDonald, which provided beef for communities downriver; that farm is still by his heirs today. His son donated an acre of his lands for the island's first school in 1890; the school was used as a community gathering-place, with the local chapter of the Odd Fellows Association meeting there from 1893 onwards, and Methodist circuit services were held there. A Baptist Church built in those times was to later become Nicomen Community Hall. A post office was named "Nicomen" was also established in 1890.
In 1892, the island and areas east were incorporated as a municipality, with three post offices at "Nicomen", "North Nicomen" (now Deroche), and "Squakum Lake" Lake Errock).
As of 1892, only 6% of the island was cultivated, 72% being woodland, and 22% "swamp, marsh and pasture". Spring freshets would regularly flood much of the island, with major floods of the Fraser inundating the island in 1882 and 1894. As with neighbouring farm communities in the Fraser Valley, one of the island's principal agricultural sectors was, and is, dairy farming. In the early 1900s a local steamer operated by the Western Condensed Milk, Cannery, Coffee and Creamery Company ran from their cannery adjacent to the Fraser in Mission, bringing in six tons of milk a day from Nicomen Island and other communities in between.