The Enfield Blackwater, locally known as the Blackwater at Longwood, is a 15-mile river flowing through Counties Kildare and Meath in Ireland's east midlands. Rising from its source in the north of County Kildare near Timahoe, the river winds northwest past Knockanally Golf Club, through Johnstown Bridge, and along the Kildare-Meath county border. It passes under the M4 motorway west of Enfield and beneath the Royal Canal via the Blackwater Aqueduct before veering northward near Longwood and ultimately draining into the River Boyne just below Inchamore Bridge. This is a classic Irish wild brown trout river, offering 16 miles of fishable water from Johnstown Bridge downstream to its confluence with the Boyne — all managed by the Longwood Angling Association. The river features high banks in places, but numerous accessible stretches provide excellent opportunities for fly anglers seeking wild fish in a scenic midlands setting.