Non research-intensive institutions of higher education are effective at narrowing STEM gender gaps in major selection and persistence to degree completion, yet the decision to attend such a setting is likely seen as counterintuitive when such institutions typically have lower levels of research, financial resources, and total student enrollments in the sciences. This case study identifies institutional factors reported by "STEM-Promising" females, defined as females who completed at least one Advanced Placement (A.P.) STEM course in high school, as influencing their decision to attend their non research-intensive undergraduate institution. Using a quantitative, cross-sectional research design and original survey, 23 out of 45 factors were reported to influence their college choice. Significant differences between STEM and non-STEM majors were noted in the influence of undergraduate research opportunities, faculty reputation, graduate/professional school admission, presence of academic support/tutoring, and the graduate program available at the institution. For STEM majors also admitted to research-intensive universities, only university size and average class size at the non research-intensive institution were reported as superior to the research-intensive. Additional non research-intensive undergraduate institutions are encouraged to repeat this study at their own institutions and tailor their institutional marketing and admissions materials to reduce the STEM gender gap.