Johor–Singapore Causeway

The Johor–Singapore Causeway is a 1.056-kilometre (0.66 mi) causeway consisting of a combined railway and motorway crossing that links Malaysia's second largest city of Johor Bahru across the Straits of Johor to the district and town of Woodlands in Singapore. It was the only land connection between the two from 1923 until 1998, when the Tuas Second Link opened. The distance between Singapore's Woodlands Checkpoint and Malaysia's Bangunan Sultan Iskandar is approximately 2.4 km (1.5 mi). It also serves as a water pipeline between the two countries, with untreated water being sent to Singapore, and some of the treated water being sent back to Malaysia.

It is one of the busiest border crossings in the world, with 350,000 travellers daily. A vast majority of these travellers are Malaysian citizens working or studying in Singapore for its more desirable education and employment opportunities, in part due to the strength of the Singapore dollar over the Malaysian ringgit as well as a higher quality of life. A few continue to reside within Johor and commute daily with either public or private motorised transportation to and from Singapore, enduring long journey times with extremely heavy traffic congestion on weekdays. The border is handled by immigration authorities of both countries at the Southern Integrated Gateway (Malaysia) and Woodlands Checkpoint (Singapore) respectively.

Both countries permit pedestrians to walk along the entire length of the causeway on foot, although this is not common and is generally limited to instances of standstill vehicular congestion throughout the partial or entire length of the causeway, which prevents passengers from boarding regular-hour cross-border public buses after clearing immigration.