modules/locale.nix

{
  time.timeZone = "America/New_York";
  i18n.defaultLocale = "en_US.UTF-8";

  i18n.extraLocaleSettings = {
    LC_ADDRESS = "en_US.UTF-8";
    LC_IDENTIFICATION = "en_US.UTF-8";
    LC_MEASUREMENT = "en_US.UTF-8";
    LC_MONETARY = "en_US.UTF-8";
    LC_NAME = "en_US.UTF-8";
    LC_NUMERIC = "en_US.UTF-8";
    LC_PAPER = "en_US.UTF-8";
    LC_TELEPHONE = "en_US.UTF-8";
    LC_TIME = "en_US.UTF-8";
  };

}