The Six Mile River is in fact closer to 20 miles long than six. Known as the River Ollarbha and at the beginning of the 17th Century, Owen-na-View or River of the Rushes to the ancient Irish, the river rises in a spring in Ballyboley Park Moss to the south west of Shanes Hill. It flows down in a tiny ravine into the townland of Headwood and forms a boundary between the baronies of Upper Glenarm and Upper Antrim. On leaving Ballycorr, the river flows gently towards Ballyclare, bisecting the Main Street, before it leisurely meanders through the Six Mile Valley until it reaches Dunadry where it was a prominent feature in the local mill, now the Dunadry Inn. Continuing its course, the river flows past Muckamore Abbey on its way to Antrim Bay on the shores of Lough Neagh.
Accounts vary as to why the river is known as the Six Mile. The most widely accepted story is that Norman soldiers marching from Carrickfergus Castle to Antrim calculated that they had marched six miles when they forded the river near Ballyclare and so began to call the Ollar the Six Mile Water.