As a Canadian Passport holder you would need either a passport or Nexus card when travelling to the US by air.
For travel by land or water, An enhanced driver’s licence (EDL) or enhanced identification card (EIC) from a province or territory where a U.S.-approved EDL/EIC program has been implemented is accepted
Canadian citizens 15 years of age and under require proof of citizenship, such as an original or a copy of a birth certificate, or an original Canadian citizenship card. Canadian citizens 18 years of age and under who are travelling with a school or other organized group, under adult supervision with parental/guardian consent may also present proof of citizenship alone.
The most important formality on entering the United States is providing proof of your Canadian citizenship. Your Canadian passport is the best document to prove your Canadian citizenship and your right to return to Canada.