It hasn’t been such a smooth ride for Canadian retailers lately.

Montreal-based clothing chain Le Chateau has struggled to keep its head above water amid dwindling sales and higher inventory for several quarters in a row.

Toronto women’s chain Tabi has already disappeared, shuttering its 76 locations in late 2011. Montreal’s once ubiquitous Jacob has cut back significantly, closing about a third of its stores in recent months. And Vancouver-based children’s apparel chain Please Mum has closed 68 of its 90 stores this year.

Even large chains aren’t immune. Sears Canada is in the midst of a major reorganization, trying to turn around the iconic 60-year-old department-store in the face of rapidly changing consumer demands.

The causes have been slightly different, but now, even those that remain face a similar threat: big-budget U.S. retail chains eager to set up shop. Despite the pitfalls, their reasons for doing so are obvious: compared to the U.S., we have fewer places to shop, and the ones we do have make more money

A recent report by real estate consultancy Colliers International found that the U.S. has 23 square feet of retail space per person. The comparable figure in Canada is 14 square feet — although Canadian malls average annual sales of $580 for every square foot of retail space available, well above the $309 seen in the U.S. (All currencies are Canadian.)

Here are six U.S. chains that are eager to take advantage of that: