U.S. Imports of Goods by Customs Basis from Canada (IMPCA)

Source: U.S. Census Bureau  

Source: U.S. Bureau of Economic Analysis  

Release: U.S. International Trade in Goods and Services  

Units:  Millions of Dollars, Not Seasonally Adjusted

Frequency:  Monthly

Further information related to the international trade data can be found at https://www.census.gov/foreign-trade/data/index.html
Methodology details can be found at https://www.census.gov/foreign-trade/Press-Release/current_press_release/explain.pdf