Even in a vehicle, you need a CCW to legally carry a loaded handgun. If its loaded and under your seat, under a shirt, in the glove box or hidden anywhere else in and around your person, it is considered concealed. You can conceal it in your vehicle if its unloaded or disassembled. This doesnt apply to rifles and shotguns because by Idaho law, they cant be concealed.
But i believe Idaho honors every other States concealed firearm liscense
States that Honor Idaho's CCW Permit:
Alabama, Alaska, Arizona, Arkansas, Colorado*, Florida*, Georgia, Idaho, Indiana, Kentucky, Louisiana, Michigan*, Missouri, Montana, New Hampshire, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Wyoming
* Honors RESIDENTIAL Idaho permits only.
State CCW Permits that Idaho Honors:
Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, Wyoming,
It is also legal to carry a concealed firearm w/out a liscense as long as you are outside city limits and engaging in legal activity. Statute 18-3302 12(d)(g) says:
" (12) The requirement to secure a license to carry a concealed weapon under this section shall not apply to the following persons:
(d) Any person outside the limits of or confines of any city while
engaged in lawful hunting, fishing, trapping or other lawful outdoor
activity;
g) Any person who has a valid permit from a state or local law
enforcement agency or court authorizing him to carry a concealed weapon. A permit issued in another state will only be considered valid if the permit is in the licensee's physical possession."