The Complete Fly Tying Recipe Library

The American March Brown is a classic dry fly used to imitate Maccaffertium vicarium, one of the larger and more important spring mayflies found across the eastern United States and Upper Midwest. Despite its name, the hatch often occurs in May rather than March and usually develops as a steady trickle instead of a dense emergence. The fly is commonly tied in sizes 8 through 12 and can be fished with a drag-free drift or blind-cast through riffles, runs, and likely holding water. Because trout feed on March Browns throughout the emergence, nymph, emerger, wet-fly, and spinner versions can all be productive in addition to the traditional dry fly.