Update 3/5/2019
The information is this guide is still valid.

Update 5/19/2017
This still works!

Update 2/26/2016:
The info in this guide is still current. I'm going to a LAN party tomorrow and was able to spin up a dedicated server for Insurgency by following this guide.

Update 8/27/2015:
There are now four different coop modes and many more maps, I've added information about them so the info is easy to find on what maps are available and the coop modes they support.

Update 2/15/2015:
Thanks to Arc in the comments for providing additional advice. Arc has a greatly detailed guide that you can find here. If you just want to get a server up quickly, this guide will work. If you want to know more and actually learn what you are doing, check out Arc's guide.

This guide explains how I was able to get a dedicated server setup for a LAN party. Setting up a dedicated server for Insurgency was very difficult to do and I had to use numerous guides to piece the info together. Hopefully this can help someone else not waste as much LAN party time as I did. I'm sure many of the veterans in this community know a ton more about setting this up than what I have figured out. Please leave a comment and let me know and I'll update the guide with any new information.

1. Create a folder for SteamCMD and the dedicated server to install to (For this example we use D:\steamcmd)
   
2. Download SteamCMD for Windows http://media.steampowered.com/installer/steamcmd.zip
   
3. Unzip SteamCMD to D:\steamcmd
   
4. Run steamcmd.exe
   
5. Enter the following commands at the prompt:
   
   login anonymous app_update 237410 validate quit

Note: The app_update command will start an 9GB download.

• Open the folder:
  
  D:\steamcmd\steamapps\common\Insurgency Dedicated Server
• Create a batch file (start.bat) with the following command:
  
  srcds.exe +maxplayers 32 +sv_lan 1 -console sv_playlist coop +mp_coop_lobbysize 8 + mp_coop_min_bots 1 +mp_coop_min_bots 8 +mp_coop_max_bots 10 -lobbysize 10 -ins_bot_difficulty 1 +map district_coop

• Start Insurgency game
  
• Alt-tab back to the Windows desktop
  
• Run
  
  Start.bat
• Alt-tab back to Insurgency game and click on Server Browser. You should now see your local dedicated server in the LAN tab. You might have to click the Refresh button.

1. At the server command prompt (the command window that opened when you ran Start.bat), you can change maps during play. The command window doesn't look like an actual prompt, but you can type these commands in and they will work.
   
   
2. To change a map enter the following command at the servers command prompt:
   
   map district_coop checkpoint

Currently the following maps are available:

PVP (day) maps:
buhriz - command to change to this map: map buhriz
district
embassy
heights
market
ministry
panj
peak
revolt
siege
sinjar
station
tell
uprising
verticality

PVP (night) maps:
buhriz_night - command to change to this map: map buhriz_night
contact
district_night
embassy_night
heights_night
market_night
ministry_night
panj_night
peak_night
revolt_night
sinjar_night
station_night
tell_night
uprising_night
verticality_night

COOP (checkpoint) maps:
buhriz_coop - command to change to this map: map buhriz_coop checkpoint
district_coop
embassy_coop
heights_coop
market_coop
ministry_coop
revolt_coop
siege_coop
sinjar_coop
tell_coop
verticality_coop

COOP (hunt) maps:
buhriz - command to change to this map: map buhriz hunt
buhriz_night
contact
contact_night
district
district_night
embassy
embassy_night
heights
heights_night
kandagal
kandagal_night
market
market_night
ministry
ministry_night
panj
panj_night
peak
peak_night
revolt
revolt_night
siege
sinjar
sinjar_night
station
station_night
tell
tell_night
uprising
uprising_night
verticality
verticality_night

COOP (outpost) maps:
buhriz - command to change to this map: map buhriz outpost
buhriz_night
contact
contact_night
district
district_night
embassy
embassy_night
heights
heights_night
kandagal
kandagal_night
market
market_night
ministry
ministry_night
panj
panj_night
peak
peak_night
revolt
revolt_night
siege
sinjar
sinjar_night
station
station_night
tell
tell_night
uprising
uprising_night
verticality
verticality_night

COOP (survival) maps:
contact - command to change to this map: map contact survival
contact_night
district
district_night
embassy
embassy_night
heights
heights_night
kandagal
kandagal_night
market
market_night
ministry
ministry_night
panj
panj_night
revolt
revolt_night
siege
sinjar
sinjar_night
station
station_night
tell
tell_night
uprising
uprising_night
verticality
verticality_night

COOP (conquer) maps:
buhriz - command to change to this map: map buhriz conquer
buhriz_night
contact
contact_night
district
district_night
embassy
embassy_night
heights
heights_night
kandagal
kandagal_night
market
market_night
ministry
ministry_night
panj
panj_night
peak
peak_night
revolt
revolt_night
siege
sinjar
sinjar_night
station
station_night
tell
tell_night
uprising
uprising_night
verticality
verticality_night