I live in the U.S., but worked the summer in Canada -- is my 4,500 taxable in the U.S.?

As stated in the questions, I received 4,500 from my summer job in Canada, but I'm a U.S. citizen. Will I need to pay tax in the U.S. on that income? If so, how do I report it?

As a US person you are taxable on all your income from any source. So the Canadian income is taxable just like any other income. You may be entitled to a credit or a deduction for any Canadian taxes that were withheld from your income, or you may be able to file a refund claim in Canada. You should consult a Canadian tax advisor on the latter point.

If that is your only income you likely will not owe US tax, but you should consult the instructions at www.irs.gov to determine whether you have an obligation to file an income tax return anyway.

Yes you will .... if that's all you made, you are eligible to file your return electronically AND get help for free ... www.irs.gov