sshd not setting locale

**Edit: I should have mentioned in my original question that I was using MacPorts SSH client, as it turned out there were two root causes. See my own answer below.** When I SSH into my OSX machine, it's not setting the locale properly: LANG= LC_COLLATE="C" LC_CTYPE="C" LC_MESSAGES="C" LC_MONETARY="C" LC_NUMERIC="C" LC_TIME="C" LC_ALL= This should be using a UTF-8 locale. It should look like this: LANG="en_US.UTF-8" LC_COLLATE="en_US.UTF-8" LC_CTYPE="en_US.UTF-8" LC_MESSAGES="en_US.UTF-8" LC_MONETARY="en_US.UTF-8" LC_NUMERIC="en_US.UTF-8" LC_TIME="en_US.UTF-8" LC_ALL= I'm running OSX 10.11.6 (El Capitan), and I've enabled the SSH server in System Preferences. I'm using putty as a client on my Windows machine. When I use the same putty configuration to connect to a Linux server, the locale information is fine. When I run a local terminal on the OSX machine, locale is fine. If I then ssh localhost, I have the same problem: no locale is set. It seems that my OSX SSH server is ignoring or discarding the locale information from the client. I have the following in my (unmodified) /etc/ssh/sshd_config: AcceptEnv LANG LC_* To the best of my knowledge, that's all that's required. My putty configuration is sending TERM=xterm-256color, which is being honored; it's only the locale information that isn't working, and to reiterate, it happens when I ssh localhost from OSX to itself, so I don't think putty is the issue here. **I will not accept answers that suggest setting the locale in my .profile; there are plenty of answers on here suggesting that, but it's a hack, not a solution.**