List of churches in the USA is available in Wikipedia. You can also find this information by visiting christianitytoday website.
Church lists are available from many data providers. You can buy the up-to-date church email lists from InfoGlobalData.
Church email addresses are available from mailing list compilers. You can target specific types of Churches and denominations like Catholic church mailing list, Baptist mailing list for churches, Pentecostal church email list, Covenant & Evangelical church email addresses, Churches with daycare, Churches with schools and place your church mailing list.
Email addresses of pastors in the USA are available from InfoGlobalData. These pastor email lists are permission based and are CAN-SPAM Privacy Compliant.
Email list of churches can be built by doing your own research using google. Go through Church directories, Christian associations website and copy and paste the details in an Excel sheet.
Mailing lists for churches are not free and if you are getting any database of churches free make sure you check and validate the details are up-to-date. Church emails must be permission based for email marketing usage. You can do church mailing lists and sign up to receive free church email newsletters.