If you’re planning your first trip to Ontario from the United States, you’re in for a treat. Ontario is a beautiful and diverse province that offers a range of activities and attractions for visitors of all ages and interests. Here are some of the best places and activities to do during your week-long trip to Ontario.

1. Niagara Falls – Niagara Falls is a world-famous attraction that should be at the top of your list. You can take a boat tour to get up close and personal with the falls, explore the various viewing areas, or take a helicopter tour for a bird’s eye view.
   
2. Toronto – Toronto is the largest city in Canada and offers a range of activities for visitors. You can visit the CN Tower for a panoramic view of the city, explore the Royal Ontario Museum, or take a stroll through the picturesque neighborhoods.
   
3. Algonquin Provincial Park – Algonquin Provincial Park is a beautiful park that offers a range of outdoor activities, including hiking, camping, and canoeing. The park is known for its stunning fall foliage and is a popular destination for nature lovers.
   
4. Ottawa – Ottawa is the capital city of Canada and offers a range of historic and cultural attractions. You can visit Parliament Hill, the National Gallery of Canada, or take a stroll through the ByWard Market.
   
5. Muskoka – Muskoka is a beautiful region that offers a range of outdoor activities, including hiking, fishing, and boating. The region is known for its picturesque lakes and charming small towns.
   
6. Thousand Islands – The Thousand Islands is a beautiful archipelago that straddles the Canada-United States border. You can take a boat tour to explore the islands and learn about their history, or enjoy a range of water sports and outdoor activities.
   
7. Stratford – Stratford is a charming town that is known for its Shakespearean festival. You can catch a show at the festival, explore the town’s charming streets, or take a stroll through the scenic parks and gardens.

In conclusion, Ontario offers a range of activities and attractions for visitors of all ages and interests. Whether you’re seeking outdoor adventures, cultural experiences, or scenic views, Ontario has it all. From the stunning Niagara Falls to the charming town of Stratford, there’s no shortage of things to do and see during your week-long trip to Ontario.