Mullan Road

Kootenai County · dedicated 2025 · I-90 (E Alder Creek Rd, Near Exit 28), milepost 28

Walk the Mullan Road, one of the Northwest's most significant routes. Take the side road to your left. From 1858-62, John Mullan's Army road crew built the Northwest's first engineered highway, connecting Fort Benton with Fort Walla Walla, 625 miles long. Idaho’s portion of Interstate 90—the “Captain John Mullan Highway”—roughly follows that road. Mullan's crew spent Independence Day 1861 here, giving Fourth of July Summit its name. They carved that date into a white pine. The famed Mullan Tree became a popular tourist stop before foresters removed the diseased tree in 1988.

TodayHistorical map

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David Rumsey Map Collection, Stanford Libraries

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under a mile from where William Gabby lived in the 1760s

what this marker records spans 1777 to 1789, overlapping William Gabby's years here

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