Probably a few thousand miles. I haven’t seen them sell milk in gallon sizes around here. The quart is common, and I think I’ve seen the half gallon (or 1000 and 2000 mL, if you want to be accurate), but no gallons. Maybe in large cities.
If you want to know how far to a grocery store, then about a few hundred meters. Little store on the corner than shows no signs of flagging since the giant superstore came last year.
From home: about a ten minute walk to the local supermarket, where I could buy 2 x 2 litres of milk.
From the office: about 50m across the road to the supermarket.
I live directly across a small street from a gas station, so maybe 100 feet.
maybe 500ft to Walgreens? plus 200 feet or so just to get out of my condo complex.
there’s a grocery store in the same plaza but milk at Walgreens actually seems to be cheaper.
Right across the street. No more than 50 feet.
About .5 miles walking, 1.3 miles driving to Walmart. There’s also a gas station .9 miles driving that sells milk. The walking route is very direct, but only has pedestrian access across the creek.
According to Google Maps, about 170 metres from the door of my apartment building to the Valu-mart across the road. In my continuing quest to become in better shape, I run the route door to door now. 
During the day and evening, about 2-3 city blocks to the grocery. Unfortunately, after 10, most everything in my town is closed. At that point, it is a 10 mile drive to an all night gas station, 19 miles to a Walmart in one town, 22 miles to another. Either way, not a short enough trip…
Brendon Small
There is a grocery store about 7 blocks west of me, and about 5 blocks away in several different directions there are convenience stores, but if I were buying milk, it would be in litres. And, well, I don’t often buy milk.
I’m astonished so many people have to travel so far for milk. I only need to walk four blocks to a 7-Eleven. I can also buy milk at a corner store a block-and-a-half-away, but they only sell half gallons.
A block and a half, but I’m lactose intolerant.
Same here, I don’t think I can get gallons anywhere nearby. It’s pretty much only sold in liters (2-liter occasionally) around here.
For a liter, I might only need to go downstairs. There’s a convenience store in the lobby of my building that sells snacks and emergency goods (diapers, tampons, etc.) and may sell dairy.
Other than that, looking at google maps there are three full convenience stores and two supermarkets within 300m of the front door.
I’m on the corner of an intersection of two main streets. Across the street one way I have a deli, across the street the other way I have an upscale grocery store, a health foods store, and a Walgreens, and diagonally across the street I have a large grocery store & a Rite Aid.
So… not very far.
I’d have to go about 2 blocks, though I’d rather not buy my milk at a liquor store. The nearest actual grocery store is about half a mile.
I’ll see your 1000km and raise you another 6000km (Auckland to Honolulu)… a further 3000 if Hawaii is out of stock and we have to head to LA.
1,2 or 3 liters… meh… 400m to the nearest service station… 3km to the supermarket.
2 minutes’ walk most of the time. 5 minutes for 24-hour convenience.
Somewhere close to ten miles. I can get it down to over five if I buy a couple half-gallons at a gas station convenience store, but it’s more expensive.
Half a mile to the 7-11, or just over a mile to Safeway.
I’m less than two miles from 3 different convenience stores, and about 4-5 miles from two actual grocery stores (in opposite directions).
A gallon comes out to about 3.78 litres, most I’ve seen on sale in the UK is 3 litres at Tesco or Sainsbury’s. If I’m buying that much it’s about a mile to the nearest one from the house.