She went to the hospital yesterday.

Literal

She [topic-は] yesterday, hospital [to-に] went.

病院に行く ('go to the hospital') in Japanese routinely covers both visits to large hospitals and small clinic appointments — 病院 ('hospital') is broader than English 'hospital' and overlaps with what English would call a 'clinic' or 'doctor's office.' Healthcare in Japan is universal under the national insurance system, and walk-in visits to neighborhood clinics for minor illnesses are normal — 病院に行く isn't necessarily the dramatic event the English equivalent often suggests. The に here marks the hospital as the destination of motion.