Costume Shop Finder Northampton Costume Shop Listings page. This section lists as many Costume Shops we could find in Northampton. If you are the owner of a Costume Shop in Northampton please submit your listing using the Get Listed link at the top. These Northampton Costume Shops offer costumes and fancy dress for adults or children in Northampton, including theatrical and party costumes, Halloween costumes and costume accessories. Most Costume Shops listed below also offer costume accessories such as masks, wigs, make up and props in Northampton.