From the ProPublica site: Use this database to view summaries of 3 million tax returns from tax-exempt organizations and see financial details such as their executive compensation and revenue and expenses. You can browse IRS data released since 2013 and access more than 14 million tax filing documents going back as far as 2001.

Voluntary directory of nonprofit organizations that can be searched by name, keyword or geography. Requires free registration for financial and other information. Guidestar also sells access to more detailed information through subscription.

INRC database of Iowa community nonprofit organizations. Use the Directories tab at the top of the site for similar information on state and national levels.

UI hosted organization that brings together resources and expertise to benefit the Iowa nonprofit community.

From the site: mission is to develop and disseminate high quality data on nonprofit organizations and their activities for use in research on the relationships between the nonprofit sector, government, the commercial sector, and the broader civil society.

For University of Iowa students, faculty and staff. Resources for finding research grants and external funding for other needs.

Formerly Guidestar and The Foundation Center. Connects nonprofits, foundations, and individuals to the resources they need to do good, building on 88 years of dedicated experience.

The Foundation Center makes many of their resources available to the public through collections in local libraries around the country. Often, local librarians are trained to help you use Foundation Center resources.

Clearinghouse for federal grant programs. Read the "who is eligible for a grant" in the About Grant.gov section before spending a lot of effort here.

Public/private partnership site with, "...tips, tools, and information to navigate the world of behavioral science research, from formulating your question to getting your proposal funded"