The term hemp manila rope is commonly used but inaccurate.
Manila rope is made from a hard fiber, a member of the banana plant family known as abaca. It is readily available.
Hemp rope is made from a soft fiber, the industrial (non-drug) strain of the cannabis plant family. While it is available on some specialty sites in some sizes and putups, it is difficult to find and can be costly.*
Cannabis has not been grown for sale in a number of countries, including the United States, for most of the past 100 years (except as a manila substitute during World War II) because of concerns that the non-industrial type would also become available and be processed for drug use. And while restrictions on growing the industrial variety are being eased in the U.S. and some other areas, it’s likely producers of fabrics, paper, oils, foods and other non-cordage related products will take advantage of the new supply.
While hemp rope is one of the oldest types, it began to lose ground vs stronger (approximately 20 percent stronger), tougher manila about 200 years ago. And since synthetics have replaced natural fiber cordage in most load bearing / safety related applications, market demand may not justify initiating production.
It should be noted that organic hemp rope is available on some of these sites, so the effort and cost may be worth while for those for whom this is a major consideration.