At about 1.5 inches leg span, it is the largest I have seen. Sometimes they are called 'fiddlebacks'. They are very common in houses here.
If you have these you probably will not have very many other insects in the house. They also stay out of sight and do not spin webs in the open.
Too bad they are poisonous. During 36 years in this house no bites have been confirmed.
I seem to have reduced the numbers significantly using sticky paper floor insect traps in all rooms.
This photo is used here : Maryland
(Loxosceles reclusa) Reference: BugGuide.Net