Build 42 is not a small map extension. The official 42.20 release more than doubled the practical scope of exploration through new western towns, full town reworks, basements, skyscrapers, randomized wilderness and thousands of unique buildings. Exact Build 41 route guides should be treated as historical unless they have been rechecked on the current B42 layer.
Quick answer
Official 42.20 figures: about 1,400 new unique buildings and 20,000 new tiles, taking the total from roughly 15,000 to 35,000.
Build 42 adds Ekron, Irvington and Brandenburg and fully reworks Riverside, West Point, Rosewood, Fallas Lake, Muldraugh, Ekron and Dixie.
Build 41 saves are not compatible with Build 42; 42.19 saves also cannot transfer to 42.20 because of additional map content.
At a glance
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| System | Build 41 | Build 42.20 |
|---|---|---|
Map scale | ~15,000 tiles total | ~35,000 after +20,000 tiles |
Buildings | More repeated structures | +1,400 unique buildings delivered in the new pass |
New towns | Classic east/central layout | Ekron, Irvington, Brandenburg + smaller locations |
Basements | Not a broad world system | 400 procedural + 75 unique basements |
Height | Previous height limits | Up to 32 zombie-filled floors in Louisville |
Map edges | Fixed civilized boundary | Huge randomized wilderness expanses |
World variation | More fixed | World seeds affect generated basements/wilderness/zombie distribution |
New towns and the western expansion
The most obvious Build 42 change is the west. Ekron, Irvington and Brandenburg are the three headline new towns, with additional smaller locations and rural content filling the enlarged county. This means old “the west is mostly empty” assumptions are no longer useful.
Seven locations received the full 42.20 glow-up
Official 42.20 notes list Riverside, West Point, Rosewood, Fallas Lake, Muldraugh, Ekron and Dixie as entirely reworked. The standard includes unique buildings/houses, consistent landscaping and custom tiles. Route instructions based on identical Build 41 houses or old school locations should be rechecked.
The map is vertical now
Basements, bunkers and hidden underground spaces can exist below suitable buildings, while Louisville skyscrapers can extend up to 32 zombie-filled floors. A “building location” is no longer only an X/Y problem. Stairs, basement exits and floor-by-floor fatigue can matter just as much as the street.
Randomized wilderness and world seeds
The map edges now include huge randomized wilderness expanses, and official documentation notes that seeds can influence generated basements, wilderness and zombie distribution. Fixed town streets remain navigable, but a screenshot cannot prove that every generated basement or rural detail will match your save.
Save compatibility and old-guide policy
Build 41 saves are not compatible with Build
42. The 42.20 release also states that 42.19 unstable saves cannot transfer because extra map content was added.
Troubleshooting and common mistakes
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| Problem | Fix |
|---|---|
An old POI screenshot does not match | Switch to a current B42 map layer and verify the town was not part of the 42.20 rework. |
I cannot find the basement shown in another save | Generated basements can vary by seed; verify whether the location is fixed or procedural. |
My old save will not load | Build 41 saves do not transfer to Build 42; use the legacy branch if you want to finish them. |
FAQ
How much larger is the Build 42 map?
Official 42.20 materials say the map surface area doubled, with about 20,000 new tiles added.
Which towns are new?
Ekron, Irvington and Brandenburg are the three headline new towns.
Which towns were fully reworked for 42.20?
Riverside, West Point, Rosewood, Fallas Lake, Muldraugh, Ekron and Dixie.