Loud unidentified boom that shook houses and was heard in at least 8 towns at the same time.I am reporting an unidentified loud boom that was heard at 9:00pm eastern time across many towns in central Maine. It sounded similar to a sonic boom and shook the house. It was felt by my immediate neighbors in West Gardiner, by my sister in Litchfield, a friend in Richmond and in Gardiner. Facebook lit up with many reports also in the towns of Pittston, Farmingdale, Chelsea, Monmouth, all occurring at 9:00pm or 22:00 (sic. 21:00). News investigation turned up nothing, and USGS reported no seismic activity in the state. I looked but saw nothing unusual outside immediately after the boom, however the report by so many individuals in so many towns at the same time of the same unidentified boom in my opinion is worth reporting.((NUFORC Note: Source of the report elects to remain totally anonymous; provides no contact information. PD))