Lincoln was ready to move Washington DC to Kearney, Neb. had he lived. Records show it was all surveyed and set up to have it moved to have the Center of the US located in the geographical center of the Nation.
So he planned to acquire Greenland? (What else would shift the center from Lebanon, Kansas to Kearney, Neb.?)
I checked and Kearney Neb is slightly west of Lebanon KS. Greenland might match the latitude but not the longitude.
Adding Alaska and Hawaii shifted the center from Lebanon KS to Castle Rock SD.
I’m pretty sure that wasn’t Lincoln. Nebraska wasn’t a state then and it wasn’t too far from what could be hostile Indian territory. There was talk later of moving the capital there.
https://history.nebraska.gov/new-washington-in-nebraska/
Whether such talk was serious or not hard times in the 1890s put an end to it.
There was talk after the Civil War about making St. Louis the capital. I recall hearing that Woodrow Wilson wanted a summer capital in Colorado Springs, but the internet doesn’t confirm this. It may just have been that he liked spending summers there. Lincoln did set up a “federal city” in Port Angeles, Washington, for military, naval, lighthouse and trade purposes, leading some to think of it as a potential second capital later, but that wasn’t going to happen.