Royal River

{{about||the ancient canal or river in Mesopotamia|Naarmalcha|the 1959 Canadian documentary film|Royal River (film)}}

{{Use American English|date=February 2025}}

{{Infobox river

| name = Royal River

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| name_other = Westcustogo River (former)
Pumgustuck River (former)
Yarmouth River (former)

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| image = Royal River, Yarmouth, Maine.jpg

| image_size = 250px

| image_caption = The Sparhawk Mill on the Royal River in Yarmouth, Maine, a few hundred yards northwest of its mouth at Casco Bay

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| subdivision_name1 = United States

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| length_mi = 39

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| source1 = Sabbathday Lake

| source1_location = New Gloucester, Maine

| source1_coordinates= {{coord|43|59|18|N|70|20|58|W|display=inline}}

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| mouth = Casco Bay

| mouth_location = Yarmouth, Maine

| mouth_coordinates = {{coord|43|47|51.4|N|70|10|37.9|W|display=inline,title}}

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The Royal River is a small river, {{convert|39|mi}} long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. [http://viewer.nationalmap.gov/viewer/ The National Map] {{webarchive |url=https://web.archive.org/web/20120329155652/http://viewer.nationalmap.gov/viewer/ |date=2012-03-29 }}, accessed June 30, 2011 in southern Maine. The river originates in Sabbathday Lake in New Gloucester and flows northeasterly into Auburn and then southerly through New Gloucester (via the Royal River Reservoir), Gray and North Yarmouth into Casco Bay at Yarmouth.

The river is bridged by Interstate 95 and U.S. Route 202 before leaving New Gloucester, then by the Maine Central Railroad "Back Road" and the Grand Trunk Railway in Auburn, and then again by the Grand Trunk Railway and by State Route 231 when it returns to New Gloucester. The river is bridged twice more by the Maine Central Back Road in Gray. In North Yarmouth, the river is bridged again by State Route 231 and by State Route 9, and in Yarmouth it is crossed by the Maine Central Railroad "Lower Road", again by the Grand Trunk Railway, by U.S. Route 1 and, at its mouth at Yarmouth Marina, by State Route 88 (carried by the East Main Street Bridge) and, finally, Interstate 295.

The Native Americans called the river Westcustogo River (meaning muddy) or Pumgustuck River (falls at mouth of river).[https://rrct.org/royal-river-water-trail/ The Royal River Water Trail] – Royal River Conservation Trust

During the 1700s and 1800s, Yarmouth River, as it was then known, was a source of great economic growth for Yarmouth as it provided the power for the many mills. One such mill was erected in 1872 by the Forest Paper Company on the current site of the Royal River Park.

The river is mentioned in several of Maine-native Stephen King's novels, including The Body, when the boys cross the Royal River, only to be attacked by leeches, as well as 'Salem's Lot and Rita Hayworth and Shawshank Redemption. The McKin Company Superfund site was within the Royal River watershed.{{cite web

| title = Site Information McKin Company Superfund Site Gray Maine

| publisher = United States Environmental Protection Agency

| date = 1985-07-22

| url = http://www.clu-in.org/products/costperf/THRMDESP/Mckin.htm#SITEINFO

| access-date = 2009-07-21 }}

In 2005, the Royal River was named a restoration priority by the Gulf of Maine Council, part of the Marine Environment and the Maine State Planning Office. In 2009, the town brought in an engineering firm to recommend cost-effective avenues of restoring fish access and native species to the Royal River. The following year, Stantec recommended the removal of both dams, as the lowest-cost and longest-term solution. In 2025, Yarmouth's town council unanimously approved the removal of the dams at the Second and Fourth Falls.{{Cite web |date=2025-01-10 |title=Yarmouth approves Royal River dam removal to restore waterway and its inhabitants |url=https://www.pressherald.com/2025/01/10/yarmouth-approves-royal-river-dam-removal-to-restore-waterway-and-its-inhabitants/ |access-date=2025-03-14 |website=Press Herald}}