Boyne River is a stream in Northern Michigan, named for the River Boyne in Leinster, Ireland. Together with the north and south branches, the river system has approximately of mainstream and the water basin drains . Boyne River is Lake Charlevoix's second-largest tributary, after the Jordan River.
Boyne River's mainstream is approximately long, from the confluence of the north and south branches at less than a mile northwest of the village of Boyne Falls . The main branch flows northwest through Boyne City into Lake Charlevoix at .
The North Branch Boyne River is long and rises in Hudson Township in eastern Charlevoix County at . The South Branch Boyne River is long and rises in Elmira Township in northwest Otsego County at . The South Branch flows northwest across the northeast corner of Warner Township in Antrim County.
The river system has three major impoundments: the Boyne City Mill Pond, a reservoir formed by a hydroelectric dam, and the Boyne River Pond.
The Boyne City Mill Poind is in Boyne City, less than a mile from the river's mouth. The Mill Pond is not a true impoundment resulting from a dam on the river, but affects the river similarly in that it collects sediments and provides a large surface area that tends to raise the water temperature during the summer months. The pond is called "Little Lake" in a 1901 plat book.
A hydroelectric dam owned by Boyne Resorts forms a reservoir at coordinates (southwest of Addis Road and southeast of Drury Lane). The dam was built circa 1906 to provide power to nearby towns. The Boyne River Power Company merged with many other small power providers in West Michigan to form the Michigan Public Service Company in 1927. Consumers Energy bought that company in 1950. They continued to operate the power plant until October 12, 1962, after which the generating equipment was removed and the dam. They sold the buildings and land surrounding the reservoir to the Boyne Mountain Lodge in 1963. In 1982, the Boyne Mountain Resort received a license to operate a 250-kilowatt hydroelectric generator using the existing dam and reservoir.
The Boyne River Pond is located on the South Branch near Boyne Falls (at coordinates ). The dam was built before 1900; the water flow powered a saw mill and grist mill. the M-75 highway crosses the river over the dam.
The soils surrounding Boyne River's headwaters are primarily composed of a Kalkaska-Leelanau association (a mixture of Kalkaska and Leelanau sands). These soils tend to form steep riverbanks. Among the fish species living in Boyne River are chinook salmon, walleye, brook trout, brown trout, and rainbow trout.
The Boyne River system drains all or portions of the following cities, townships, and villages: