By default the parser assumes your address has a zip code in it. But by setting the force_post_code_flag to 0 you can get around this,
my $ap = Lingua::EN::AddressParse->new(country => 'US', , force_post_code => 0);
my $error = $ap->parse('1 Main St, Silver Spring, MD, USA');
die $error if($error);
print $ap->report();
Original Input '1 Main St, Silver Spring, MD, USA'
Cleaned Input '1 MAIN ST SILVER SPRING MD USA '
Country address format 'US'
Address type 'suburban'
Non matching part ''
Error '0'
Error descriptions ''
Warning '0'
Warning description ''
Case all '1 Main St Silver Spring MD USA'
COMPONENTS ''
base_street_name 'Main'
building ''
country 'USA'
level ''
po_box_type ''
post_box ''
post_code ''
pre_cursor ''
property_identifier '1'
property_name ''
road_box ''
street_direction_prefix ''
street_direction_suffix ''
street_name 'Main'
street_type 'St'
sub_property_identifier ''
sub_property_type ''
subcountry 'MD'
suburb 'Silver Spring '
