The present disclosure relates to semiconductor structures and, more particularly, to contact structures to deep trench isolation structures and methods of manufacture. The structure includes: a deep trench structure lined with insulator material on sidewalls thereof; conductive material filling the deep trench structure; a local oxide extending above the trench on exposed portions of the insulator material; an interlevel dielectric material on the local oxide and the conductive material filling the deep trench structure; and a contact in the interlevel dielectric material, extending to the conductive material and on a side of the local oxide.