$re = '/^.*?\s[N]{0,1}([-a-zA-Z0-9]+)\s*\w*$/m';
$str = '2038 W MAIN AVE
2038QWEW S JEFFERSON AVENUE
33 NORTH CALIFORNIA STREET
53371 SOUTH WASHINGTON
53371 S WASHINGTON AVENUE
1600 E PENNSYLVANIA AVE
WEST9 67ST ST
E171 N 23RD STREET
G171 N121ST STREET
G171 N121ST SQUARE';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php