Custom Archive page using custom Taxonomies Pagination issue

I’m creating a site that displays a ton of billboard locations for a client. I created a custom post type for the billboards(billboard_location) and a custom taxonomy(location) which holds the county that the billboard is in.

The idea is to click on a link of the County and have WP return a list of all of the billboards. It sounded so simple….. lol

In researching this I found that only the archive.php file deals with sorting taxonomies, so that is the file I’ve been modifying for my results.

First I pass a parameter to a session that captures what county the user clicks on. Then I created a custom loop that uses that county and returns the results.

All this works fine. But a few counties have over a hundred billboards, so I want to paginate the results to only show 12 at a time. This is where the issue is.

The pagination code breaks the returned posts into groups of 12 and displays the navigation at the bottom. But whenever you click on a page like(i.e. page 3) it starts to redisplay the first set of twelve, shows the first post and then stops.

I’m on day 2 of fixing this and any help would be greatly appreciated!!
(here is a link to the live page with the county of York as an example: https://thespotbeta.com/trone-outdoors/index.php/billboard_location/?county=york)

Here is the Loop:

//Start the Loop if County is specified

if($county != ''){
$paged = ( get_query_var('paged') ) ? get_query_var('paged') : 1;

$args = array(
'post_type' => 'billboard_location',
'location' 	=> $county,
'posts_per_page' => 12,
'paged' => $paged);
$bill_loc_query = new WP_Query($args);
if ($bill_loc_query->have_posts()) {
while($bill_loc_query->have_posts() ): $bill_loc_query->the_post();
get_template_part( 'content-billboard_locations', get_post_format() );
endwhile;	

if (function_exists(custom_pagination)) {
custom_pagination($bill_loc_query->max_num_pages,"",$paged);
}
} else {
// If no content, include the "No posts found" template.
get_template_part( 'content', 'none' );
}
session_unset();

And here is the pagination code:

function custom_pagination($numpages = '', $pagerange = '', $paged='') {

  if (empty($pagerange)) {
    $pagerange = 2;
  }

  /**
   * This first part of our function is a fallback
   * for custom pagination inside a regular loop that
   * uses the global $paged and global $wp_query variables.
   *
   * It's good because we can now override default pagination
   * in our theme, and use this function in default quries
   * and custom queries.
   */
  global $paged;
  if (empty($paged)) {
    $paged = 1;
  }
  if ($numpages == '') {
    global $wp_query;
    $numpages = $wp_query->max_num_pages;
    if(!$numpages) {
        $numpages = 1;
    }
  }

  /**
   * We construct the pagination arguments to enter into our paginate_links
   * function.
   */
  $pagination_args = array(
    'base'            => get_pagenum_link(1) . '%_%',
    'format'          => '&page=%#%',
    'total'           => $numpages,
    'current'         => $paged,
    'show_all'        => False,
    'end_size'        => 1,
    'mid_size'        => $pagerange,
    'prev_next'       => True,
    'prev_text'       => __('?'),
    'next_text'       => __('?'),
    'type'            => 'plain',
    'add_args'        => false,
    'add_fragment'    => ''
  );

  $paginate_links = paginate_links($pagination_args);

  if ($paginate_links) {
    echo "<nav class='custom-pagination'>";
      echo "<span class='page-numbers page-num'>Page " . $paged . " of " . $numpages . "</span> ";
      echo $paginate_links;
    echo "</nav>";
  }

}