Catholic Network of Volunteer Service is a US based non-profit organisation established in 1963 which has as its mission "to be a bridge between people thinking about volunteering and member programs, over 230 of which offer volunteer opportunities." The site features information for both programs seeking volunteers and those seeking a place to volunteer.
The site has specific information for volunteers and for volunteer programs and underlines its importance as a national network of service movements.
https://www.cnvs.org/aboutus/index.php