I have often found that the easiest way to explain ccw reciprocity is to try to compare it to a drivers license. You see when you obtain a drivers license from any state in this country you know it is valid in every other state in the country. You perhaps have never thought about it but can you imagine driving into the neighboring state, getting pulled over, and being told by the officer that they don't honor licenses from your state. The federal government regulates it. This is why you can't have more than one drivers license at the same time.
Concealed carry permits are far different. Until recently states did not have to offer concealed carry permits at all. Recently a federal court ruled that Illinois had to begin a concealed carry program. Now, while all states must somehow allow citizens to carry concealed weapons, each state varies significantly in their system to issue permits. Because states have such unique processes and qualifications for citizens to obtain permits, states are less likely to feel that they can honor permits from other states.
As an example, in Nevada citizens must take a lengthy class that includes classroom instruction and range time. In Idaho citizens need only pay a fee and pass a background check. You can see while Nevada would be distrusting of people who have an Idaho concealed carry permit. In their view, Idaho permit carriers don't meet the Nevada state qualifications to have a permit.
Therefore, each state has a list of what other state permits they will honor. Only Utah and Texas honor ALL permits regardless of what state they come from.
Colorado is unique beyond most other states. In addition to having a specific list of states that we honor, we also only honor permits in the hands of residents of the state where the permit was issued. If you have a Colorado concealed carry permit you are probably not very concerned with knowing which states permits are honored in Colorado. More, you want to know which states honor the Colorado Concealed Carry Permit. That is what the below map represents.
States in Blue honor the Colorado Permit. States in Red do not. When you are traveling you need to do your own research. You can' always trust a map on some random website. While there are a lot of good websites and mobile applications where you can do the research you may want to contact the state where you are planning on spending time.