The south and east sides of North Brother drains into a swampy area called "The Klondike", then into Wassataquoik Stream, the East Branch of the Penobscot River, and into Penobscot Bay. The north and west sides of North Brother drain into Little Nesowadnehunk Stream, Nesowadnehunk Stream, and the West Branch of the Penobscot River.
^"PRISM Climate Group, Oregon State University". PRISM Climate Group, Oregon State University. Retrieved September 28, 2023. To find the table data on the PRISM website, start by clicking Coordinates (under Location); copy Latitude and Longitude figures from top of table; click Zoom to location; click Precipitation, Minimum temp, Mean temp, Maximum temp; click 30-year normals, 1991-2020; click 800m; click Retrieve Time Series button.