Like how would Charles Ingalls have gotten salt for preserving his meats? Pepin, Wisconsin is hundreds of miles from the ocean (or any other naturally-occurring salt water), and AFAIK the number of salt mines in the region is/was equally limited. Is there some ancient way of extracting salt from animal blood or minerals or something?
Wouldn’t you just buy it (or trade for it) like you would any other product you wanted? I can’t see any reason why salt, or anything else that’s located far away, wouldn’t have easily made it’s way to anywhere that there are people willing to pay for it.
Charles Ingalls was around, let’s call it 150 years ago. In the mid 1800’s there should have been plenty of general stores with suppliers and distributors just like we have now.
Salt has been traded since time immemorial. The legendary Timbuctu existed in large part because of its salt trade; nowadays salt is about the only thing left moved on the route to the central Sahara. 150 years ago is trivial.
There are natural salt deposits throughout the US, too (though, as others have said, it’s far more likely that Ingalls bought his salt).
Quote from Little House in the Big Woods: "The nearest town was far away. Laura and Mary had never seen a town. They had never seen a store. They had never seen even two houses standing together. But they knew that in a town there were many houses, and a store full of candy and calico and other wonderful things: powder, and shot, and salt, and store sugar.
They knew that Pa would trade his furs to the storekeeper for beautiful things from town, and all day they were expecting the presents he would bring them."
They would often locate the animals’ salt licks and go from there.
Even today most people get their salt at a store.
Also, a point you apparently haven’t considered–people without a ready source for mineral salt didn’t have mineral salt. You can survive without adding salt to food and there are other ways to cure meat.
Cite? Salt licks don’t contain pure sodium chloride, and generally contain a lot of other minerals as well. This would be a pretty inefficient and unappetizing way to get your salt. Maybe people might do it if they were a very remote area and really desperate, but usually people will trade for pure salt if they can.
While a lot of natural salt licks are mostly minerals other than salt, some are. E.g., Blue Licks, KY.
Salt seeps/springs were another way of getting salt. E.g., in PA and NY.
La Crosse had a population of > 7000 in 1870, is that the town Pa would go to, or would it have been a closer, smaller town?
Thanks, Brian
Pepin is on the Mississippi so wouldn’t be isolated from any commodity that was widely traded, which salt certainly was. Even in somewhat more remote areas, like Walnut Grove MN where that family also lived, there were of course people in the business of transporting goods to those places, albeit expensively and inefficiently by later standards. It seems possible a poor settler might have had trouble coming up with cash or credit to buy enough salt to do a lot of meat preservation using it, but not so plausible salt would not have been around at a price.
Besides salt imported from long distances, there as was a growing salt producing industry around the Great Lakes by mid 19th century based on evaporating natural brine in underground (or under lake) deposits, and/or mining it dry, in Ohio and Michigan for example. Now the biggest source of salt in the region is from mines partly under Lake Huron near Goderich Ontario, where road salt distributed from Milwaukee for example mostly comes from. Those mines started producing ca. 1860’s.
Looking on a map, Pepin is farther north than I remember. Wabasha and Winona are possibilities (though are across the river). Buffalo City?
Brian
Read Salt. It’s an amazing book on the history of salt. Truly fascinating. Every civilization, every group of people in history made sure they had access to salt. Because if they didn’t, they died.
One of my all-time favorite books. The story of how Venice became a merchant empire is quite engrossing. 
It’s been quite a while since I read that, but I did know even beforehand that salt is the one food product that EVERYONE on earth uses.
That’s one reason why salt is the food product selected for iodization.
Here’s a quote from the Indian Pioneer Papers describing the production of salt for one community…
"There is a place near Salina that has salt springs, I well remember when I was a small boy, my parents and some of the neighbors would go there every year to make salt for their year’s supply.
They had three large kettles, four feet across the top and about three feet deep. They would build up a large fire under each of these kettles and fill them up with this salt water and boil it until the water was all boiled away. Then they would take out the salt that was left in the kettles.
As near as I can remember we got about three or four gallons at a salt cooking, and the part I played in making this salt was to keep the fires burning for there had to be just so much fire burning all the time under each kettle and it was up to us boys to keep that fire just so."
Hence, why it was called Salina. 
Daniel Boone and the settlers had to risk their lives obtaining salt for the winter.
Boone was captured at the Blue Salt Licks and held for several months. He escaped in time to warn the settlers before the siege of Boonesborough.
A major Revolutionary war battle was fought there too.
appropos here is a mention of the wonderful documentary Saltmen of Tibet, which chronicles the sacred journey selected tibetan yak herders make to the salt lake to bring home salt to their villages. Really worth seeing.