alternatehistory.com

...That would bring in navvies and workers, expand local economic conditions, open up land for settlement and expansion, require a larger garrison which means more soldier settlers and their families...
... the new infrastructure generated ...would be a magnet for immigrants.

...the timber trade will open up, it will be much easier to settle as far up as Michigan (which will have other economic developments in its favor) and Ontario will probably end up being "full" in the 1840s-50s prompting desires to expand further West.
...once the railroad booms begin that will simply add to the profitability of the colonies, which weren't resource poor OTL
Given that's true, & IMO it all is, what does that mean for the success of, frex, the Erie Canal? Would the U.S. (or Britain) controlling the entire St. Lawrence mean Erie is never built?

Does the Seaway's existence affect the size, or growth, of Chicago & Detroit, & Winnipeg? The Seaway suggests more Lakes trade earlier, meaning growth of Wisconsin & Michigan iron & other mining, & possibly wagon manufacturing in Michigan &/or Indiana. (Enough to move the center of auto manufacturing in the late 19th Century?) That also suggests impact on ship construction for Lakes trade: larger wooden ships, following the pattern of the steel Lakes freighters, dedicated to Lakes trade? (Or is that too 20/20 hindsightish?)

IMO, the fur trade means (what became) Thunder Bay is going to be bigger, & OTL Churchill (Manitoba) smaller, because of shipping across the Lakes, rather than through Hudson Bay.

Are there other impacts of doing this? Does it change the size of New York City, or Boston?

Does this impact Western migration? It would seem to be easier to reach the "upper West" (western Ontario along the Superior coast, Wisconsin, southern Manitoba & Saskatchewan, Minnesota, & the Dakotas) much sooner, especially compared to Oklahoma, never mind Oregon overland.

Are there implications I've missed?
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