Tucked along the shores of Lake Winnipesaukee at Weirs Beach, Endicott Rock State Historic Site preserves one of New England’s most significant colonial boundary markers. In 1652, surveyors dispatched by Massachusetts Bay Colony Governor John Endicott carved inscriptions into this large glacial boulder, marking what they determined to be the northernmost headwaters of the Merrimack River — and thus the edge of Massachusetts’s territorial claim. That bold survey triggered a boundary dispute between Massachusetts and New Hampshire that wouldn’t be settled until King George II intervened in 1741.

Today the rock sits within a protective stone-and-iron enclosure near the channel where Lake Winnipesaukee flows outward toward the Merrimack River system. Interpretive signage walks you through the colonial power struggle this unassuming boulder set in motion. At just 0.1 acres, this is a quick stop — plan for 10 to 15 minutes — but the history packed into this spot punches well above its size.

The real draw is pairing Endicott Rock with everything Weirs Beach offers. The MS Mount Washington lake cruise departs nearby, the Winnipesaukee Scenic Railroad runs along the waterfront, and the boardwalk’s arcades and eateries are steps away. It’s an easy addition to a full day at the lake.

Visit between late May and mid-October for the best weather and access to surrounding attractions. Summer weekends at Weirs Beach get lively, so arrive early if you prefer a quieter experience. There’s no camping on-site, but several campgrounds and state parks dot the Winnipesaukee shoreline within a short drive.

Explore Nearby

• Kancamagus Scenic Byway — Scenic Byway in New Hampshire
• White Mountain National Forest — National Forest in New Hampshire, Maine
• White Mountain Trail — Scenic Byway in New Hampshire
• Union Village Covered Bridge — Covered Bridge in Vermont
• Sayres Covered Bridge — Covered Bridge in Vermont