You can file in any county. However the respondent can file a motion for change of venue to the county of his residence (unless he was served in the first county). This is not an issue if you file as co-petitioners.
John H. Barrett
728 Pearl St.
Boulder Co. 80302
Generally, the correct county is the county where the Respondent lives. If you file in a different county and the opposing party does not object then the case will move forward despite the incorrect venue. All District Courts have general jurisdiction so any court will be able to hear the case. However, if you file in the wrong venue and the other party objects, they can ask to have to case moved to the correct county. If this happens, the case may be delayed briefly, but will untimately proceed in the new county once it is moved.
You can reach Harkess & Salter LLC at (303) 531-5380 or info@Harkess-Salter.com. Stephen Harkess is an attorney licensed in the state and federal courts of Colorado. This answer is for general information only and does not create an attorney client relationship between Stephen Harkess or Harkess & Salter LLC and any person. You should schedule a consultation with an attorney to discuss the specifics of your legal issues.
Counsel have both provided you with answers that are right on point. You can also file and serve him in the county where he works if this is different from where he lives. Some people prefer to avoid certain counties where it takes a year or more to get a day of judicial time. There are a couple of those in the Metro area. In Denver, people needing court time are often before a judge within 90-120 days for permanent orders.