SourceCoopSourceCoop Black Mesa Map Names: Start Co-op at Any Chapter
Every Black Mesa chapter with its map names, so you can start a SourceCoop server or changelevel to any chapter, from bm_c0a0a Inbound to Xen and Nihilanth.
Updated Oct 7, 2026 · 4 min read
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To start a SourceCoop server at a specific Black Mesa chapter, set the start map to that chapter's first map, for example bm_c1a1a for Unforeseen Consequences or bm_c2a5a for Surface Tension, either with +map on the launch line or with changelevel in the server console. Map names follow the pattern bm_c<number>a<number><letter>, and each chapter's first map ends in a. The full list is below.
Why start partway through
Black Mesa's campaign is long, and co-op groups rarely finish it in one sitting. Starting at a chapter lets you:
- Pick up where you left off on a fresh server.
- Skip the slow opening tram ride for a group that has seen it many times.
- Jump straight to a favorite like Surface Tension or the Xen chapters.
SourceCoop keeps weapons and ammo between maps, but when you start at a later chapter there is no earlier progress to carry, so expect to start with less gear than a group that played through would have.
Earth chapters
| Chapter | Map names |
|---|---|
| Black Mesa Inbound | bm_c0a0a, bm_c0a0b, bm_c0a0c |
| Anomalous Materials | bm_c1a0a, bm_c1a0b |
| Unforeseen Consequences | bm_c1a1a, bm_c1a1b, bm_c1a1c, bm_c1a1d, bm_c1a1e |
| Office Complex | bm_c1a2a, bm_c1a2b, bm_c1a2c |
| We've Got Hostiles | bm_c1a3a, bm_c1a3b, bm_c1a3c |
| Blast Pit | bm_c1a4a, bm_c1a4b, bm_c1a4c, bm_c1a4d, bm_c1a4e |
| Power Up | bm_c2a1a, bm_c2a1b |
| On A Rail | bm_c2a2a, bm_c2a2b, bm_c2a2c |
| Apprehension | bm_c2a3a, bm_c2a3b |
| Residue Processing | bm_c2a4a, bm_c2a4b, bm_c2a4c, bm_c2a4d |
| Questionable Ethics | bm_c2a4e, bm_c2a4f, bm_c2a4g, bm_c2a4h |
| Surface Tension | bm_c2a5a through bm_c2a5i |
| Forget About Freeman | bm_c3a1a, bm_c3a1b |
| Lambda Core | bm_c3a2a through bm_c3a2h |
Note that Surface Tension skips bm_c2a5b, so do not try to load it.
Xen chapters
| Chapter | First map |
|---|---|
| Xen | bm_c4a1a |
| Gonarch's Lair | bm_c4a2a |
| Interloper | bm_c4a3a |
| Nihilanth | bm_c4a4a |
The Xen chapters span many more maps than the Earth ones. Start from the first map of each chapter to be safe, since SourceCoop's map data expects the normal entry points.
How to set the start map
On the launch line
./srcds_run -console -game bms -port 27015 +maxplayers 10 +mp_teamplay 1 +exec server.cfg +map bm_c2a5a
The server boots straight into that map every time it starts. Change it again when your group moves on, or it will keep starting from the same chapter after every restart.
While the server runs
In the server console, or through RCON from your game:
changelevel bm_c3a1a
Everyone on the server moves to the new map. Use this when the group wants to skip ahead mid session.
Checking the name
If you mistype a name, the server reports that it cannot find the map. List the map files in bms/maps/ to see the exact names, or type maps bm_c2 in the server console to list everything starting with that prefix.
Picking good stopping points
The first map of a chapter is the cleanest place to resume a session, because it lines up with Black Mesa's own chapter select. Some stretches are long, so plan nights around them:
- Inbound to Office Complex is a relaxed first evening.
- We've Got Hostiles to Power Up is the heaviest Earth combat, great with a full group.
- Surface Tension is a long chapter on its own and worth a full night.
- Xen changes the pace completely, and the boss fights get loud with several players.
Known problem maps
Some maps hang or crash during load for certain setups, the Nihilanth map bm_c4a4a being the best known. The usual fix is turning off mod_forcetouchdata, which stops map data pre-caching:
mod_forcetouchdata 0
Put it in bms/cfg/server.cfg and restart. The SourceCoop crash and connection fixes guide has more on this and other load problems.
Resuming a campaign between sessions
SourceCoop does not keep a save file of where your group stopped the way single player does. The practical way to pick up next time:
- At the end of the night, note the map the server is on. Type
statusin the server console and it shows the current map name. - Before the next session, set that map, or the first map of its chapter, as the start map.
- Restart the server before everyone joins.
Starting from the chapter's first map is safer than a mid chapter map, because some later maps expect you to arrive through a level transition with doors and triggers already in a certain state.
On a hosted server
On a GamezServers SourceCoop server, the Starting Map field in the control panel sets the map the server boots into, bm_c0a0a by default. Change it to any name from the tables above and restart. The live console takes changelevel for jumping mid session, and the advanced mod_forcetouchdata toggle is right there in the panel for maps that hang. Need the full setup? See how to host a Black Mesa co-op server with SourceCoop.
FAQ
What is the first map of Black Mesa?
bm_c0a0a, the start of Black Mesa Inbound.
What map does Surface Tension start on?
bm_c2a5a.
How do I skip to Xen on a SourceCoop server?
Run changelevel bm_c4a1a in the server console, or set it as the start map and restart.
Why does the Nihilanth map crash my co-op server?
It is known to hang on load with map data pre-caching on. Set mod_forcetouchdata 0 and restart.
Skip the setup. Your own SourceCoop server.
Then $4.99/mo. Just trying it? $1.25 for 3 days
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