Achieving an interoperable health care system remains a top US policy priority. Despite substantial efforts to encourage interoperability, the first set of national data in 2014 suggested that hospitals’ engagement levels were low. With 2015 data now available, we examined the first national trends in engagement in four domains of interoperability: finding, sending, receiving, and integrating electronic patient information from outside providers. We found small gains, with 29.7 percent of hospitals engaging in all four domains in 2015 compared to 24.5 percent in 2014. The two domains with the most progress were sending (with an increase of 8.1 percentage points) and receiving (an increase of 8.4 percentage points) information, while there was no change in integrating systems. Hospitals’ use for patient care of data from outside providers was low, with only 18.7 percent of hospitals reporting that they "often" used these data. Our results reveal that hospitals’ progress toward interoperability is slow and that progress is focused on moving information between hospitals, not on ensuring usability of information in clinical decisions.