A Map of Lake Powell, and Why the Shape Matters

Lake Powell is not a lake in the shape anybody pictures. It is a drowned river canyon: the Colorado River's old course, backed up behind Glen Canyon Dam, with dozens of side canyons flooded along its length so that the outline on a map looks less like a lake than like a branch of coral.

That shape, and one fact about the roads, explains most of the decisions you will make about a trip here.

Where it is

Lake Powell straddles the Utah–Arizona border, with the great majority of its area in southern Utah and its downstream end in northern Arizona. It sits inside Glen Canyon National Recreation Area, which is administered by the National Park Service.

The town at the downstream end is Page, Arizona, a few miles from the dam and from Wahweap Marina. Page is the practical base for most visitors: it has the airport, the hotels, the supermarkets and the hospital, and it is the meeting point for the Antelope Canyon tours.

Getting there means driving, for nearly everybody. Page is several hours from Las Vegas, from Phoenix, and from Salt Lake City, and it sits within reach of a run of national parks — Zion, Bryce Canyon, Capitol Reef, the Grand Canyon's North and South Rims, and Monument Valley — which is why so many people arrive here as one stop on a longer southwestern loop.

The layout, from bottom to top

The lake runs roughly southwest to northeast, and it is conventional to describe it from the dam upstream.

Glen Canyon Dam and Wahweap, at the downstream end in Arizona. The dam, the visitor center, the largest marina, and Page nearby. Just up-lake are the wide waters of Padre Bay and the long side canyons of Navajo Canyon and Last Chance Bay.

Antelope Point, a few miles east of Wahweap on Navajo Nation land, with its own marina and its own operator.

The middle lake, reached from Bullfrog on the north shore and Halls Crossing directly opposite on the south. This is the Utah-side hub, roughly midway along. From here you reach the Escalante arm and its narrow side canyons, Good Hope Bay, and canyons such as Forgotten Canyon with its cliff dwelling.

Rainbow Bridge, in a side canyon roughly fifty miles up-lake from Wahweap and a shorter run down-lake from Bullfrog — which is to say it is genuinely far from everywhere.

The upper end, toward Hite, where the Colorado enters. This is the shallowest part of the reservoir and the first stretch to be affected when the water level falls.

At full pool the lake is close to 190 miles long with something like 1,900 miles of shoreline once every side canyon is counted. It is bigger than people expect, and it is long and thin rather than broad.

The fact that decides your trip: there is no road along the lake

This is the single most useful thing to understand before booking anything. The lake sits in a canyon system, and no highway follows it. The marinas are reached by separate roads coming in from different directions, and two marinas that face each other across the water can be a long drive apart.

Bullfrog and Halls Crossing are the clearest example. They are opposite one another across a channel. A vehicle ferry crosses between them when it is running — and whether it runs has depended on water level and season, with extended suspensions — and when it is not running, the drive around is well over two hours on remote roads.

The consequence: the access point you choose is the stretch of lake you will see. A houseboat cruises at about the speed of a brisk jog. Repositioning to a different part of the lake mid-trip is not realistic. Choose the marina and the stretch of water together, which is what which Lake Powell marina to launch from is for.

Mile markers and finding things

On the water, the lake is signed by mile markers counting upstream from Glen Canyon Dam. Marinas, canyons and features are commonly given by their mile number, and it is the quickest way to make sense of directions from anybody local.

Side canyons look remarkably alike from open water, particularly in flat midday light, and the entrance to the one you want is often not obvious until you are inside it. Carry a proper lake map — the printed navigation charts sold in Page and at the marinas are the traditional answer and remain a good one, because they carry canyon names, mile markers and hazards in a form that does not need a signal.

Cell coverage across most of the lake is patchy at best and absent in the canyons, so a navigation plan that depends entirely on a phone is a plan with a single point of failure.

Why the map changes

A printed map shows the shoreline at some assumed water level, and Lake Powell's level moves — seasonally with the snowmelt, and across years with the state of the Colorado River basin.

When the lake is lower, the shoreline retreats up the canyons, some narrow inlets become dry washes, beaches appear where there were none, and rock that was safely under a boat becomes a hazard. An old chart is at its most dangerous precisely where it matters most. Lake Powell's water level covers how to read the current elevation and what each range of it changes on the water.

What to settle next

With the geography straight, the two decisions left are where to get on the water and when to come.

Which Lake Powell marina to launch from compares Wahweap, Antelope Point, Bullfrog and Halls Crossing — what each one reaches, and what each one costs you in driving.

When to visit Lake Powell covers what each season trades away, including the spring problem that nobody mentions until you are out in it.