Everything in this post is derived from a single line spoken by BMO during Imaginary Resources. When Finn asks BMO to perform a search for Susan, BMO reports that she is “32.7 miles east of here”. At this time, Finn and BMO are on Better Reality Island and Susan is on the abandoned Hub Island.

So first things first, we need to establish which islands are which. Here is a handy map (drawn by Alva during Mysterious Island) on which I have annotated the islands according to the following evidence:

The island in the southwest is the first island Alva draws, which means it is reasonable to assume that this is their current location, Back-to-Nature Island. Additionally, this is the furthest island from the mainland, so it makes sense that it would be the last one the humans attempted to colonise. For similar reasons, the northeast island is most likely Founders’ Island. This also most closely resembles the island on the transport ship’s chart seen in The Invitation. This means the remaining two islands are Better Reality Island and Hub Island, and we already know that Hub Island is to the east of Better Reality Island thanks to BMO’s statement.

In Imaginary Resources, Finn and Jake arrive in the south of BR Island from Back-to-Nature Island. By re-orientating the above map and overlaying it onto the transport’s navigation map from The Invitation, I can draw a straight east-west line between the south of Better Reality Island and the north of the abandoned Hub Island, where Susan is waiting on the beach in Hide and Seek. As BMO said, these two points are 32.7 miles apart, which I’ve rounded to 30 for the sake of simplicity.

That extra sticky-out bit on Founders’ Island is probably a result of Alva’s poor cartography skills. Alternatively, it could be an artificial extension to the island which was not built until after Alva left.

Now, it becomes possible to calculate any other distance between two points in Ooo. Here’s the official map of the Land of Ooo (taken from The Adventure Time Encyclopaedia) with the calculated distance key added:

In the raw image, one mile is equal to five pixels, but Tumblr’s compression will probably cause that to be different on your end. Here’s a link to the raw image in case you want to make your own measurements.

Here are some measurements I took:

The width of the Land of Ooo, from easternmost point to westernmost point of the mainland, is about 280 miles (450 km).



The height of the continent, from the tip of the Ice Kingdom to the southernmost point of the Desert Lands, is about 240 miles (390 km)

The distance from the Tree Fort to the Candy Kingdom is about 46 miles (74 km). Finn and Jake must make use of Jake’s shapeshifting to make the journey in a reasonable amount of time.

The distance from the Tree Fort to the Ice Kingdom is about 28 miles (45 km).

The distance from the Tree Fort to the Fire Kingdom is about 100 miles (160 km).

The distance from the coast of Ooo to Founders’ Island is about 210 miles (340 km). Assuming a good speed of 5 knots, it would take a sailboat like the Sugar Spit about 36 hours to make the journey, although the Sugar Spit obviously got a boost from Whipple.

Just for fun, here’s a quick comparison showing the Land of Ooo alongside the US and the UK:

There are rounding errors at every stage, so don’t use this as absolute precise proof of the size of the Land of Ooo.

This is something I’ve wanted to do for a while, and it was good fun. Hope you enjoyed.