The short answer is that if you have the right facility on file, it will get there.
Every jail and prison in the United States is required to accept mail delivered through the United States Postal Service. That is not a policy that varies by state or county. It is a baseline that applies across the board, which is why InmateAid routes everything through USPS. Postcards, greeting cards, photos, and letters all go out the same way, and InmateAid has been doing this without interruption since 2012.
One thing worth knowing is that some facilities only accept postcards and will reject standard letters or photos on sight. If that is the case for Carson County Jail, InmateAid already knows it. The platform accounts for facility-specific mail rules when processing your order, so you are not sending something that will get turned away at intake.
The only variable that matters on your end is whether the facility and inmate information you entered is correct. If the address is right, InmateAid guarantees delivery. If you are uncertain whether your inmate's location is current, double-check before sending. A transfer to a new facility after your order goes out is the most common reason mail does not reach someone, and that has nothing to do with the carrier or the platform.
If you ever have a question about a specific order, InmateAid's support team can confirm the status and resend at no charge if something goes sideways.