Dozens of neighborhoods in at least three Seacoast communities will take part in the 29th annual National Night Out Against Crime. The event will be celebrated in Portsmouth, Rochester and Seabrook on Tuesday, Aug. 7.

In Portsmouth, which is participating for the 18th year, the national event is co-sponsored by the Portsmouth Police Department and the Citywide Neighborhood Committee, with support from Seacoast Crime Stoppers. Social activities and block parties will take place across the city with the goal of strengthening neighborhood cooperation and police-community partnerships.

The Seabrook Police Department and Seabrook Watchdog are joining forces to host National Night Out for the first time. They are encouraging residents to get together with neighbors for barbecues and walks around town.

Rochester, too, will take part in the celebration with support from Bridging the Gaps. There will be food vendors, youth performances, local organizations, children’s games and bounce houses from 5 to 8 p.m. in the Union Street Parking Lot.

The non-profit National Association of Town Watch started National Night Out in 1984 to heighten crime- and drug-prevention awareness, strengthen neighborhood spirit and build support for anti-crime programs.