Passenger Manifests - Boston 1848-1891Searchable database of immigrants who arrived in the port of Boston by ship, from the Massachusetts Archives. The collection is in the process of being digitized; contact the Archives if you don't find the name you're looking for.
"Massachusetts officials started recording the names of immigrants who arrived by ship in January of 1848, a procedure which continued until July of 1891, when federal records-keeping programs superseded those of the state. Although immigrants arrived at numerous Massachusetts ports, the Archives holds manifests for BOSTON ONLY." (from the site)