The phrase "accessible only at the" is correct and usable in written English.
It can be used when specifying a location or condition under which something can be accessed.
Example: "The document is accessible only at the designated secure server."
Alternatives: "available solely at the" or "retrievable exclusively at the".
See bournemouth.co.uk for a downloadable guide to the area It's an eerie experience, walking around this ghost village, accessible only at weekends when the military firing range is not in use.
However the ruins, on an island connected by a causeway accessible only at low tide, date from early in the 12th century.
Because of the house's location on the marsh, the effect of the tides means it's accessible only at certain times.
In those days the island was free of tourism, separated from the mainland by a causeway, accessible only at low tide.
I can paddle along the mouth of the Savannah River near Fort Pulaski and watch the containerships come in, or go over to Little Tybee Island and go through canals accessible only at high tide.
THE COMMUTE Three subway lines are accessible, but only at the area's perimeter.
ESCRAVOS, Nigeria — As dusk approached and the glow from the oil rig gas flares grew stronger, the oilmen, politicians and militants arrived by boat in small groups to celebrate the opening of 911 Resort, a half-finished villa accessible only by boat at the outer edge of the creeks of the oil-rich Niger Delta.
Two regions were excluded because they were accessible only by air at the time of the study, Badakhshan and Sughd.
It's the Madonna Drowned World Tour T-shirt, and it earns multiple status points at once: it's accessible only to the connected few who scored tickets to one of Madge's sold-out shows.
While their restaurants may be accessible only to the world's 0.1 percent, chefs at top restaurants influence the entire global food community with the way they think, write, tweet and talk about food — not just the way they cook it.
