Petromyzon marinus (Sea Lamprey) is a large, anadromous, ectoparasitic fish native to the Northeast Atlantic Coast. Sea Lamprey nest-building activities increase stream habitat heterogeneity, benthic invertebrate diversity, and fish density. The Sea Lamprey has undergone severe declines throughout most of its native range in part due to dams that limit access to spawning habitat. Here, we documented the spawning of Sea Lamprey in the Mill River in Taunton, MA, following stream channel reconstruction. Sea Lamprey nest-construction activities altered 129 m² and 32 m² of total streambed area within the reconstructed channel during 2014 and 2015, respectively. The association of Sea Lamprey spawning with stream restoration has important implications to the ecology of the Mill River and demonstrates that similar projects may facilitate the recovery of Sea Lamprey populations in the Northeast.