Domain website expired

Good Afternoon,
I am the secretary of Round Rock Chambermasters # 4591. We found out that our domain  www.rrtoastmasters.org/ expired on July 5th. How can we find out who is the owner of the domain so we can do the renewal? 
Thank you in advance,
Anca Ducea

Since your site admin did not post the information in the admin console it will be very hard to find out, as all that information is now hidden by the registrars.
You can try sending an email to the email flagged in the whois record.

www.name.com/contact-domain-whois/rrtoastmasters.org

Here's the link to look up domain info so you can see what Brian is referring to:
who.is/whois/rrtoastmasters.org