House Usher is a small White Court Vampire house that is subservient under House Raith. The house, and all of its members, are located in Baltimore; although before WWI they in fact controlled much of the eastern seaboard. As the ports became more influential House Raith began parsing out the territory to their favored family members and the fortunes of House Usher began to shrink.
The Usher's main house in Baltimore is located at 108 Ridgewood Rd, Baltimore, MD 21210. The rest of the properties on Ridgewood between Sunny Lane are either owned by other family members, the Raith's, or people that work with the Ushers. While these houses have been put on and off the market this is only to allow the members to launder money gained from their other businesses.
Lawrence Usher attended the dinner party hosted by Evan Montrose where he got involved in a spirited discussion with several members of the Midnighter's Club. There was never any proof offered that he had anything to do with the events of the Vampires and Indians case file.