Increasing the number of transfers and graduates in engineering who start at community colleges (CC) requires strategic partnering between institutions. Reflecting on the results of a five-year partnership between a large, multi-location CC and a large four-year university, we present the goals, conceptual framework, specific results, and best practices for developing and sustaining STEM partnerships to increase the number of transfers and graduates in engineering. There were four foundational practices to this partnership: (1) inter-institutional collaboration, (2) creating a CC engineering orientation course, (3) developing an engineering admissions partnership program for CC students, and (4) data collection and analysis for informed decision making. The specific foundational practices described in this paper are part of a larger effort to increase the persistence of CC transfers in engineering by creating or enhancing a transfer-friendly environment, a community of practice through partnerships, greater awareness about engineering and engineering careers, student-faculty interaction, and new datasets for research and evaluation. Results of the partnership include a notable increase in the number of pre-engineering students, the number of students participating in the engineering admissions partnership program, the number of students transferring to the university, the number of transfer students participating in a learning community, and an increase in first-year retention rates of CC transfer students in engineering.