[SeeSharp]

The Eastern District court is a popular place for patent infringement lawsuits and has earned a reputation as somewhere that favors patent holders in such disputes.

Marshall Texas.

There are office buildings in Marshall that have little tiny micro offices that are rented and have names on the doors, but are never actually used. Lawyers rent them so they can claim to have an office in Marshall, which in turn gets them the ability to file cases there. Patent law is a big money maker for Marshall.

[KevinB]

Any lawyer admitted in a state can file cases in any court in that state. They don’t need to have an office anywhere close in order to do so. Perhaps it’s just a matter of convenience.