The Black River Bridge carries the Fiero Truck Trail over the Black River on a one-lane timber deck in Pine Island State Forest, announced by a brown routed-letter sign at the approach. Koochiching County’s highway records identify the crossing as county Bridge No. 36506 on the County Road 101 corridor, one of the individually flagged bridges on the county’s load-posting map.
The county’s 2021 Prioritized Bridge Replacement Schedule listed 36506 among its deficient bridges slated for replacement — an $800,000 project with a proposed construction year of 2026 — though the old timber crossing was still carrying traffic in the summer of 2026.
The river beneath it flows 48 miles from its headwaters to the Rainy River, draining a 136-square-mile subwatershed that lies more than 70 percent inside Pine Island State Forest and is over 95 percent wetland and peat bog — the source of the water’s distinctive tea color. Ditched in a failed turn-of-the-century campaign to drain the bogs for farming, the Black River today tells a better story: state biologists find sensitive caddisflies and stoneflies in its upper reaches, 27 fish species along its length, and water meeting Minnesota’s exceptional-use standards in its lower stations — a quiet, high-quality river in a forest of few visitors.
Rules for this place
The border waters section of the Minnesota fishing regulations covers only the lower reach of the Black River, and the water above that point is not in it. Minnesota’s invasive species law rides home with the trailer: pull the drain plug, drain the water, and leave plants and prohibited species at the access. Part of the Black River is on the DNR’s infested waters list for spiny waterflea, which adds bait and water-transport rules for anyone leaving it; the list gives the exact reach.
Verified 2026-09-07. Rules change; check the official page before you go.
