Vast differences in the distance women would have to travel to obtain an abortion in the U.S. have persisted since 2000 – with average distances ranging from 3.2 miles (5.1 km) for women in New York to 168.5 miles (271.2 km) for women in Wyoming in 2014, according to the first study to provide national estimates of spatial disparities for all women of childbearing age in the United States, published in The Lancet Public Health journal.
Areas that saw increases of 30 miles (48 km) or more in average distance to the nearest abortion provider were concentrated in Texas, Missouri, Iowa and Montana between 2011-2014. All of these states, except Iowa, adopted more restrictive laws during this time, and had the largest proportionate reductions in numbers of clinics.
Research suggests that around half (45%) of pregnancies in the US are unintended, and 42% of these end in abortion. Of the women seeking abortions, the majority are of lower socioeconomic status, without health insurance coverage for abortion, and do not have the resources to travel long distances due to the expense of travel (particularly when this includes overnight stays) and work and family commitments. As such, the further a woman lives from an abortion clinic, the less likely she is to obtain an abortion when needed.
“How far a woman has to travel for an abortion is a key measure of access, alongside stigma, restrictive laws and financial constraints,” says author Dr Jonathan Bearak, Guttmacher Institute, USA. “Our findings illustrate the vast differences in access to abortion mapped across the US, with women in remote, rural areas facing the longest journeys for an abortion. With laws in 14 states as of 2017 requiring that women have in-person counselling followed by an 18-72 hour waiting period before an abortion, a seemingly short journey can pose a substantial barrier as women in these areas may also need to travel to and from the clinic twice.” 
The study mapped the population of women of childbearing age against publicly accessible abortion providers in the US (these clinics performed 95% of all abortions in the US in 2014), and reported the distances women would have to travel in each state and county. Clinics included in the study were those that provided more than 400 abortions a year or were affiliated with Planned Parenthood. Other locations were not included because they were not considered public points of access, were not easily identified as an abortion provider, or risked the confidentiality and safety of the abortion providers.
The study found that, on average in 2014, women need to travel 11 miles (17 km) to access their nearest abortion clinic, but distances to the clinic varied depending on state – with 23 states having an average distance of under 15 miles (24 km), 16 states averaging between 15-29 miles (24-47 km), 8 averaging 30-89 miles (48-143 km), and 3 averaging more than 90 miles (145 km).
While many women live in cities and therefore have closer access to clinics, the researchers found that one in five women in the US would have to travel more than 43 miles (68 km) for an abortion, and in some areas, the distance was significantly greater. For example, in Alaska, compared to the average distance of 9 miles (15 km) to a clinic, 20% of women would have to travel 154 miles (248 km) or further. And, women living in in rural, less densely populated counties of Montana, Wyoming, North Dakota, South Dakota, Nebraska, Kansas and Texas would have to travel more than 180 miles (290 km).
Across the country, the average distance a woman would need to travel remained largely unchanged (changes of less than a mile) in 34 states between 2011 and 2014, but this masks regional differences. Most changes in distances in other states were under 5 miles, but large changes (of more than 5 miles) were seen in Kansas and Maine where the average distance reduced (by 74 and 21 miles, respectively), and in Montana, North Dakota and Missouri where distance increased (by 46, 14 and 7 miles, respectively).
For women in Texas and Missouri, there were also substantial changes in distances to clinics – increasing by at least 57 miles (91 km) for one in five women in Texas, and by at least 27 miles (43 km) for one in five women in Missouri.
“Although policies are implemented at the state level, the consequences of restrictive legislation might not be felt equally across all counties, with women in rural counties most likely to be adversely affected by clinic closures. Abortion is an important component of reproductive health, and restricting access to abortions can lead to them being done at later gestations or under potentially unsafe conditions.” says Dr Bearak. 
The authors note that there are numerous barriers to abortion in the US, and there may be other factors that prevent women seeking an abortion despite her local clinic being close to home. They also highlight that their results may not take into account the extra distance and burden faced by women subjected to mandated counselling and waiting periods, and for women who choose to travel or whose circumstances mean that they must travel beyond their closest abortion provider.
Writing in a linked Comment, Professor Ushma Upadhyay, University of California, San Francisco, USA, says: “This study tells only part of the story, showing the median and 80th percentile distances women must travel to reach a dedicated abortion clinic. But for women seeking specific types of providers, such as those who accept Medicaid, do abortions at later gestations, or are hospital-based, the distance might be even longer. Because provider availability decreases with each week of gestation, even a week’s delay can reduce the number of providers substantially.”