Yes, in the State of New Hampshire you are legally allowed to use non-deadly force when you reasonably believe that such force is necessary to prevent or terminate criminal trespass. The statute codifying this is NH RSA 627:7 - Use of Force in Defense of Premises.
"A person in possession or control of premises or a person who is licensed or privileged to be thereon is justified in using non-deadly force upon another when and to the extent that he reasonably believes it necessary to prevent or terminate the commission of a criminal trespass by such other in or upon such premises, but he may use deadly force under such circumstances only in defense of a person as prescribed in RSA 627:4 or when he reasonably believes it necessary to prevent an attempt by the trespasser to commit arson."
The statute is relatively narrow. Shooting at someone on your lawn, is not advisable.