The Trinity River is a long one. It is often deemed the longest river entirely within Texas borders, but only if one considers the usually dry watersheds of the Colorado and Brazos rivers that spread into New Mexico as part of the geographical equation.

The subject of the 31st tracing of a Texas river with buddy Joe Starr, the Trinity rises in the pleasant, rolling prairies north and west of Dallas-Fort Worth. Its four significant forks — Clear, West, Elm and East — converge in or near the Metroplex. In that valley, the river was best known for its severe flooding, its taming, then neglect and, now, civic improvement. Firmly in one channel, the Trinity rolls down through achingly beautiful pastures, forests and fields of grain in East Texas until it spills onto the Gulf Coastal Plains and, after several deviations, into Trinity Bay.

To trace this river, we first clawed our way across two mega-metros — we started at Joe’s home base in Houston — with a combined population of 13 million and among the ugliest, most congested freeways in North America. It wasn’t pretty. And, at times, it was not at all safe driving.

We emerged from northwest Fort Worth to discover the friendly town of Decatur, which bustles from drilling activities in the surrounding Barnett Shale region. We explored the Romanesque Revival courthouse and shared excellent barbecue at Rooster’s Roadhouse on the square. Then we headed up the West Fork of the Trinity, the longest of the tributaries.

The Handbook of Texas places its source in Archer County, but well into Jack County it is pretty dry even after spring rains. Our main source was Ranger Ray at the Fort Richardson State Park in Jacksboro. He not only told us all about the buildings there — the officer’s quarters is mostly intact, others were restored with care — and key battles during the Indian wars, but also about the river and its ways. With a map hand-drawn by a colleague, he showed us where on U.S. 281 we could find the first discernible remnants of the West Fork. Meanwhile, he recommended exploring Lost Creek on the grounds of the fort, a good tip.

After locating the promised brushy vale northwest of Jacksboro, we next found the West Fork in Runaway Bay as part of Lake Bridgeport. The Trinity has blessed the entire region with multiple lakes for water supplies, flood control and recreation. This one showed the inevitable signs of drought.

Just south of the town of Bridgeport on Texas 144, we located the first wet stretch of river proper, already crowded with hardwood trees and riparian undergrowth. Also, of course, swallows dive-bombing insects around the bridge. With some light left before dusk, we tooled around the LBJ National Grassland, which is not, as one might suppose, stretches of raw prairie, but rather managed pasturelands dotted with trees.

Since we’d driven 10 hours already, it was time to settle down back in Decatur, where our culinary luck ran out at Fuzzy’s Taco Shop, also on the square. It had the look and feel of a concept chain, which it turned out to be, not unlike Freebirds World Burrito, but without the attention to detail. Didn’t matter to the locals, who happily populated the place.

The next day started with a three-hour tire delay. That crisis managed, we raced down toward Fort Worth to view the chain of lakes and parks along the Trinity inside the Metroplex. Navigating that vast agglomeration proved tough and exhausting, even with the help of three road atlases, an iPad and an iPhone.

So we settled on visiting the nearest accessible spots to the confluences of the four forks. The meeting of the Clear and the West forks was the easiest to find, located right downtown at the original location of Camp Worth. (On our Texas river tracings, forts, dams, parks, bridges and courthouses have been among the most memorable landmarks.)

Thoroughly tamed, these two forks join at a carefully landscaped spot on the Trinity Trails, a system embraced by walkers, joggers, bikers and others. Next we braved the Airport Freeway to Irving, where we looked for the confluence of the West and Elm forks. At that point, geographers agree that the Trinity River proper begins.

We parked at a golf course, followed a multi-purpose trail dedicated in 2012 to Trinity View Park. It was easy to find the river, banked with wildflowers and willows. Joe pushed on to document the actual confluence beyond mud hills employed by motocross enthusiasts, but alas, it was not to be. We came close.

Such was not the case for the meeting of the East Fork and the mother stream. After watering some large lakes east of Dallas, the East wriggles along a wide floodplain. The closest we could get to the confluence was a spot east of Ennis. We circled around this old town, then pointed the car toward Palestine and caught the full Trinity in its East Texas mode — wide, muddy, protected by a jungle of vegetation.

Palestine, like Decatur, is a remarkably revived town. This one is girdled by one of the most convenient, but still, to the visitor, confusing roadway loops. The downtown for this famed railroad center is coming back. There we discovered Denby’s American Grill, which served outstanding steak and hamburgers, and attracts a lively after-theater crowd.

The next day was spent criss-crossing the Trinity through gorgeous backcountry. At one point, we spied a large, concrete structure that partially blocked the river. It wasn’t a dam or a weir. Later, a social media follower identified it as a test lock from the period some 50 years ago when engineers considered turning the Trinity into a barge canal to serve DFW to the sea. Environmentalists intervened.

The old steamboat ports along the Trinity are mostly gone. In their place we found the broad, popular Lake Livingston, mantled in lake culture and commerce. Farther downstream, the land becomes boggy, the towns a little worn-out and the influence of the bay — part of the Galveston Bay system — palpable.

We ended our journey, aptly, in Anahuac, established in 1832 on a short bluff as a Mexican fort and port of entry for American settlers. The former military grounds, which played various roles in the Texas Revolution, have been transformed into a park. Here at this hurricane-wracked spot, one crosses a causeway to park and then hike along a narrow, crumbling peninsula where people wade out to fish in the last remnants of the Trinity.

Unlike the rest of the coast, we saw very few signs of industrial activity.

This was among our most satisfying experiences at the mouth of any Texas river. Right there in front of us was yellow green rivulets swirling into dark blue green as fresh met brackish water.

A great place to fish. And a perfect place to contemplate the role of rivers in Texas history.