We examined the diversity of environmental education (EE) in Texas, USA, by developing a framework to assess EE organizations and programs at a large scale: the Environmental Education Database of Organizations and Programs (EEDOP). This framework consisted of the following characteristics: organization/visitor demographics, pedagogy/curriculum, operations, and assessment. A database of organizations was built by surveying EE program directors state-wide. Of 237 possible organizations, 82 responded to the survey. Results showed that 6-20% of Texans are exposed to EE yearly. In 2009, each of these organizations conducted 19 programs to serve 6,000 people using only $7,500 USD (based on medians). Environmental educators most frequently used hands-on, outdoor experiments and group discussions to teach students, suggesting constructivism as the underlying learning theory in Texas EE. The field needs a comprehensive analysis of the large diversity of organizations and programs to better understand the structure and function of EE. Databases are highly effective tools in education research because they provide: 1) a source of quality research; 2) information across multiple scales; 3) networking and collaboration; and 4) comprehensive and longitudinal data for testing theories. This study provides a framework for creating large-scale databases of EE organizations and identifies patterns among and between characteristics.