Informal physics programs bring physicists together with youth and adults from local communities to engage with physics content outside of classroom settings. These public engagement or "physics outreach" programs are a significant endeavor of the physics community; however, we lack a systemic documentation of these efforts, which makes it difficult to situate physics education research on individual informal physics programs into a broader narrative. Additionally, informal physics programs have many formats and vary in terms of their audience, content, activities, and resources. It is important to understand these aspects of programs if we want them to be more equitable and inclusive. This work shows our early steps of a large project aiming to map the landscape of informal physics programs in the United States. Drawing from organizational theory, and using data collected from a national sample of programs, we have created and validated a survey for lead facilitators to capture the who, what, where, when, and why for their informal programs. After validation, we completed targeted data collection within one state as a test case for broader implementation. Our analysis of the sample (n = 18 programs at 6 institutions) shows that there are many different factors other than common presentation-style labels that are relevant, such as geographic reach, audience demographics, funding, and involvement of physics students. One notable finding is that university physics students play a big role in the operation of these programs, making them rich environments for the attention of physics education researchers and administrators at academic institutions.