The first time a local gives you directions in Hawaiʻi, you’ll probably freeze for a second. “Go two blocks mauka, then Diamond Head on Kalākaua until you hit the 45-300s.” None of those words mean what they sound like. Your GPS can route you to the pin, but it won’t translate the shorthand.

Hawaiʻi runs on its own orientation system. Part of it is Hawaiian language. The rest is a mix of landmark shorthand and a 1930s-era tax map numbering quirk that ended up stamped on every rural mailbox. Once you understand it, a lot of small confusions stop. Here’s what the locals are actually saying.

Mauka (MAH-oo-kah) means toward the mountain. Makai (mah-KAI) means toward the ocean. Those are the two directional words you’ll hear most often, and they’re the single most useful vocabulary in the entire language for a visitor who’s trying to drive somewhere.

They are not a clean swap for compass points. Mauka on the Kona coast points roughly east. Mauka in Kāneʻohe points roughly west. The direction rotates with the shoreline, because the reference is the mountain in the middle of the island, not the cardinal compass.

Both words are built the same way in ʻŌlelo Hawaiʻi. Ma is a directional particle meaning “toward” or “at.” Uka means uplands or inland, and kai means sea. So mauka is literally “toward the uplands,” and makai is “toward the sea” (Wehewehe, the Hawaiian-language dictionary project from the University of Hawaiʻi).

The reason this works so well in Hawaiʻi is geography. Every island is a volcanic cone or ridge with the mountains in the middle and the ocean all the way around. You are almost never more than a few miles from one or the other. So when a local tells you to turn mauka at the next light, you don’t need a compass. You need to look around and pick the side with higher ground.

Mauka and makai also mean something larger than driving directions. They come out of the ahupuaʻa system, the traditional Hawaiian land division that ran in a wedge from mountaintop to shoreline so each community had access to both upland farmland and ocean fishing grounds in one continuous strip (UH Mānoa Hawaiian Studies overview of ahupuaʻa). When someone says “mauka-to-makai,” they aren’t just pointing. They’re describing the shape of the land the way it’s been described here for a thousand years.

Mauka and makai handle the mountain/ocean axis. For the other axis — what a mainlander would call east and west — each island has its own shorthand, usually based on a landmark at each end.

In Honolulu and Waikīkī, nobody says east or west. They say Diamond Head (east, toward the Lēʻahi crater at the end of Waikīkī) or ʻEwa (west, toward the old plantation town of ʻEwa out past the airport). “Two blocks Diamond Head on Kalākaua” means two blocks east along Kalākaua Avenue. “Go ʻEwa on Kapiʻolani” means head west. King Street is one-way going Diamond Head. Beretania Street is one-way going ʻEwa. Once you internalize this pair, a huge chunk of Honolulu driving directions will suddenly make sense.

The island is split roughly in half by the long spine of Mauna Loa and Mauna Kea. Wet windward side is Hilo-side. Dry leeward side is Kona-side. A shop owner in Waimea saying “she lives Kona-side” means she lives on the west half of the island. Kohala-side (northern tip) and Kaʻū-side (southern tip) also show up in casual use.

West Maui is Lahaina-side. The long winding coast out to Hāna is, unsurprisingly, the Hāna-side. “Upcountry” is its own direction altogether. It refers to the cool inland slopes above Kahului, around Makawao and Kula, and locals use it as a place-direction even though it isn’t really a compass point.

Kauaʻi is the easy one. The island is a ring. Most locals point around the ring instead of using a directional shorthand. You’ll hear “toward Hanalei” or “toward Poʻipū.” The North Shore and South Shore labels are useful too. The road doesn’t connect around the Nāpali Coast, so directions on Kauaʻi always implicitly travel one way or the other around the loop.

One more thing worth knowing: inside any one town, “town-side” means toward whatever the nearest population center is, and “country-side” means away from it. In Kailua-Kona, “town-side” is toward Aliʻi Drive. In Hilo, it’s toward downtown. You’ll pick this up in a couple of days.

Drive out of downtown Honolulu toward the Windward side or the North Shore, and the street numbers on the mailboxes will start looking strange. 45-345 Kamehameha Highway. 66-437 Kamehameha. 91-270 Farrington. The hyphens are not typos. They’re a piece of civic engineering from the 1930s that ended up quietly surviving for almost a century.

The digits before the hyphen refer to a Tax Map Key (TMK) zone and section. The first digit is the zone (there are nine on each island), and the second digit is the section within that zone. The numbers after the hyphen are the actual house number on that road within that section (Hawaii Life’s explainer on the TMK system, which is still how every parcel in the state is tracked today).

So 45-345 Kāneʻohe Bay Drive decodes as zone 4, section 5, house number 345. Zone 4 is the Windward side of Oʻahu. Zone 6 is the North Shore. Zone 9 is the Leeward and ʻEwa plains. The scheme was built in 1932 so that emergency services and the post office could find parcels in rural areas where there weren’t enough streets or intersections to give every house a standalone number (Honolulu Star-Bulletin’s “Kokua Line” column on the history).

Not every part of Oʻahu uses the hyphenated system. Honolulu proper adopted standalone street addressing in 1929, and a 1942 ordinance exempted Wahiawā, Kailua, Lanikai, and Pearl City from the prefix requirement as well (Star-Bulletin, Kokua Line, July 8, 2002). So addresses in Waikīkī and Kailua Town look like mainland addresses — four-digit house numbers, no hyphens. Drive a few miles out of any of those cores and the hyphens reappear.

The Big Island takes the concept one step further. Many addresses there are six digits with a hyphen in the middle, like 73-4460 Queen Kaʻahumanu Highway. Same TMK-zone-section logic, just with more digits because the island is bigger and more rural (Papakea Collection’s TMK overview). Maui and Kauaʻi use simpler numbering in their main towns but will still surprise you out in the rural stretches.

Two practical takeaways. First, if your GPS is choking on a hyphenated address, try entering it with a space instead of a dash, or drop the prefix entirely and search by street name plus town. Second, the prefix tells you something about where you’re actually going. If the ʻEwa Beach Airbnb you just booked is 91-1234, you’re somewhere in zone 9, section 1 — which is exactly where ʻEwa Beach and Kapolei sit on the TMK map. The numbers are a sort of ZIP code for locals.

Here’s a sample of what you might actually hear, decoded.

“Take Kalākaua Diamond Head until the zoo, then go mauka on Kapahulu, and the place is on the makai side after the second light.” Translation: drive east on Kalākaua Avenue to the Honolulu Zoo, turn left (inland, toward the mountains) onto Kapahulu Avenue, and the destination is on your right (ocean side) past the second traffic light.

“We live Kona-side, 73-something on the highway, mauka side just past Kaloko.” Translation: west side of the Big Island, on Queen Kaʻahumanu Highway, inland side of the road, just past the Kaloko-Honokōhau National Historical Park exit.

“The beach access is ʻEwa of the pier, about a quarter mile, makai of course.” Translation: west of the pier (everything is makai of a pier, which is why that last part is a gentle joke).

You will get this wrong the first couple of times. It doesn’t matter. Locals are used to visitors asking for clarification, and any well-meaning driver who says “wait, which way is mauka?” will get a friendly hand gesture back. The worst thing a visitor can do here is pretend to understand when they don’t, because you’ll end up on the wrong side of an island with a sunset you weren’t expecting.

Worth keeping in your head for a road trip.

Mauka — toward the mountains, inland.

Makai — toward the ocean.

Diamond Head / ʻEwa — east / west, on Oʻahu, measured from central Honolulu.

Hilo-side / Kona-side — windward / leeward halves of the Big Island.

Lahaina-side / Hāna-side / Upcountry — west Maui / east Maui / the inland slopes of Haleakalā.

Town-side / country-side — toward / away from the nearest town center, usable almost anywhere.

Windward / Leeward — the wet (northeast-facing) and dry (southwest-facing) sides of each island, driven by the trade winds. You’ll see these on highway signs and in weather reports.

If you’re renting a car and planning to drive any of this yourself, our preferred rental partner is Discount Hawaii Car Rental, a booking broker we’ve used and recommended to HawaiiGuide readers for years. Once you’ve picked up the keys, mauka and makai will be the first two words you need.

You’ll sometimes see mauka and makai on highway signage itself — “Makai Arena,” “Mauka Lane,” “Mauka-bound traffic merge here.” They aren’t cute branding. They’re functional road signs for a state where the mountain-to-ocean axis is the most reliable piece of geography a driver has. Use the words the same way the signs do, and the island opens up a little faster.

Knowing which way mauka is also changes how you see the land. The ridges on your left and the reef flashes on your right stop being scenery and start being a set of directions.