This document describes the rationale and methods used by the National Park Service (NPS) Northeast Temperate Network (NETN) and U.S. Fish and Wildlife Service (USFWS) Maine Coastal Islands National Wildlife Refuges (MCI) for long-term monitoring of rocky intertidal habitats. The monitoring effort will collect data for key metrics representing the ecological health of the intertidal zone, and over time it will provide an indication of the trend of these metrics.