is a Japanese national highway connecting the capital cities Kagoshima and Naha of Kagoshima Prefecture and Okinawa Prefecture, respectively. With a total length of , it is the longest national highway in Japan, though it measures only on land. The highway begins at an intersection with National Routes 3 and 10 in Kagoshima. From Kagoshima, it travels southwest along the first island chain that divides the Pacific Ocean from the East China Sea. From the north to the south, it has sections on the islands of Tanegashima, Amami Ōshima, and finally, Okinawa. On Okinawa it ends at an intersection with National Routes 330, 331, and 390 in Naha.
Route description
This very unusual road has continuous numbering over disconnected segments on the islands of Kyūshū, Tanegashima, Amami Ōshima, and Okinawa. The road has a total length of on land, but it has a length of when its maritime sections are included into its total length, making it the longest national highway in Japan. It originates in the prefectural capital of Kagoshima in Kagoshima Prefecture and terminates in Naha, the capital of Okinawa Prefecture.
Kagoshima Prefecture
At its northern terminus, National Route 58 meets National Routes 3, 10, 224, 225, and 226. The segment in the city of Kagoshima has a length of about and also carries National Route 224 towards the Port of Kagoshima. At the port, National Route 224 leaves National Route 58, continuing by ferry to the city of Tarumizu beyond the stratovolcano, Sakurajima.
Heading south by ferry, the highway resumes its land route in Nishinoomote on the northern end of Tanegashima. It travels alongside the western coast of the island within Nishinoomote. Upon crossing into the town, Nakatane, the highway ventures inland, heading towards the central district of the town. Continuing south the highway crosses into the town, Minamitane on the southern end of Tanegashima. After traveling through the center of Minamitane, the highway turns northwest and heads towards the west coast of the island where the maritime section of the highway resumes at the Port of Shimama. Unlike the previous maritime section, no ferry carries the highway from Shimama to its next land segment on Amami Ōshima. In all, the highway has a length of on Tanegashima.
Resuming its land route in the Amami Ōshima city of Amami, the highway travels southeast across the island from its northeastern tip. The highway crosses through the town of Tatsugo and then returns into the city of Amami. After passing through the central part of the city, the highway curves to the south, traveling towards the island's eastern coast. It then curves to the west, heading towards the south-central part of the island. It curves to the south once and crosses into Setouchi. Upon reaching the island's southern coast, the highway curves to the southwest, heading towards the Setouchi's central district on the southwestern end of Amami Ōshima. In the center of the town the highway's land section ends once again. Like the previous maritime section, there is no ferry between Amami Ōshima and the highway's land section on Okinawa. In all, the highway has a length of on Amami Ōshima.
Okinawa Prefecture
The highway's final land segment starts near the Port of Oku in Kunigami at the northern tip of Okinawa Island. It travels around the edges of Cape Hedo from the point's eastern side to the west coast of the cape and then curves to the southwest running along the western coast of the island to the highway's southern terminus in Naha. Further to the south along the coast, the highway crosses into the village of Ōgimi. In the village the highway meets National Route 331 on the northern shore of Shioya Bay. As the highway leaves the village and crosses in the city of Nago, it curves to the west. It then meets National Route 505, and proceeds to the south, leaving the coast and crossing the bottom of the Motobu Peninsula.
As the highway approaches central Nago, it has an intersection with the Nago-higashi Bypass, an alternate route of National Route 58. Upon reaching central Nago, the highway meets the Nago Bypass, an alternate route of National Route 449. Curving to the south, the highway meets the mainline of National Route 449. Here the highway meets the western coast of Okinawa once more and continues traveling alongside it away from central Nago. Near the southern limits of the city the highway meets the northern end of the Okinawa Expressway, a tolled, limited-access highway that parallels National Route 58 to the east from Nago to Naha. The national highway continues south along the coast passing through the rural villages of Onna and Yomitan.