The 17 km (11 mi) expressway connects Butterworth, Penang in the west to Lunas, Kedah in the east.

Many maps have mistakenly labelled the section between Exit 1501 Kubang Sebang Interchange and Butterworth as a part of the E15 expressway; that is incorrect because the remaining 5-km section is not maintained by PLUS Malaysia Berhad but rather by Lingkaran Luar Butterworth (Penang) Sdn.

[1] The zeroth kilometre is located at Jalan Heng Choon Thian at Butterworth Outer Ring Road's Container Terminal Interchange.

Konsortium Lebuhraya Butterworth-Kulim (KLBK) Sdn Bhd, commercially known as Buterworth Kulim Expressway (BKE), a wholly owned subsidiary of PLUS Expressway Berhad ("PLUS Expressways",) has been awarded the concession and contract to construct and operate the highway of dual two-lane carriageway with separate motorcycle tracks and related highway facilities for the 16.78 km highway.

Upon approaching any toll plazas, highway users have to drive no faster than 60 km/h.