An additional small section south of Fort Smith is currently designated as Highway 549 (AR 549) until it is extended northward to the I-40 interchange, at which point it will become part of I-49.

Just south of Fayetteville, I-49 combines with US 71 and US 62, forming the major expressway through the northwest Arkansas metro area.

[3] On January 8, 1999, the road was fully opened to traffic and was re-designated part of an extension of I-540, with the name "John Paul Hammerschmidt Highway", in honor of a former US Representative from Arkansas.

The state of Arkansas had originally asked the American Association of State Highway and Transportation Officials (AASHTO) to allow this extension, between Fort Smith and Bentonville as I-49, to emphasize plans to extend the route from Shreveport, Louisiana, through Arkansas to Kansas City, Missouri.

[7] AHTD conducted a feasibility study of adding an interchange at AR 162 in Van Buren in 1991, with the results adopted by the Arkansas State Highway Commission in 1992.

[citation needed] One of the requirements of designation is "an active organization composed of various private and governmental groups, businesses, and agencies who are interested in preservation, enhancement, marketing, and development of the route's scenic, cultural, recreational, and historic qualities".

On May 15, 2023, work began to renumber the northernmost four exits to correlate with the correct log mile designations.

AR 549 was first opened to traffic in December 2004 as a 29.49-mile (47.46 km) route between Texarkana and Fouke.

[13] A fourth section 14 miles (23 km) long opened on November 10, 2014, when it officially became part of I-49.

The second section of road to be designated as AR 549 was the Bella Vista Bypass in the northern part of the state.

[14] The route was eventually extended to Rocky Dell Hollow Road west of Bella Vista on May 13, 2015,[citation needed] and I-49/US 71 in Bentonville in 2017 with ribbon cutting on May 10, 2017, which included a roundabout at the US 71 and then terminus of I-49.

The groundbreaking on the final section between Rocky Dell Hollow Road and the Missouri state line occurred on October 15, 2019.

[16] The bypass opened to traffic on October 1, 2021, following a ceremonial ribbon cutting held the previous day, per ArDOT.

The stretch near Fort Smith is funded because voters passed Issue 1, the Connecting Arkansas Program (permanent extension of 0.5-cent road tax approved in 2012).

This segment needs to be reevaluated because the approval was issued in December 1997 (named "US 71 relocation" in those documents) and has since essentially expired.

This likely means that the section from Fort Smith to Texarkana (approved at the same time also) will also need to be reevaluated.

On October 13, 2022, groundbreaking began on the proposed southern extension of Future I-49 with construction expected to occur 2025 and should be completed by 2035 at latest.

[19][26][27] On May 25, 2023, ARDOT announced the proposal of a new north–south route to connect AR 612 near the Northwest Arkansas National Airport to the Bella Vista bypass (I-49) near Centerton.