A new bridge is being built across the Yellowstone River at the northeast (downstream) edge of Livingston, Montana. At present there is a river use closure from Mayors Landing Fishing Access Site (FAS) 3/4 of a mile upstream of the bridge site to the US 89 FAS about seven miles down stream.
The current closure ends 12 April 2013, but information from FWP & MTDOT at a public meeting last night indicates that it will likely be extended until precast beams are laid, the deck poured and work bridge removed - maybe some time in June or July.
FWP Yellowstone River closure - Google Search
Lots of other good Class II reaches available in Park County, but if anyone has a long trip planned a lengthy portage will have to be arranged.