Researchers have long argued that where we live can help predict how we die. But how much our location affects our health is harder to say, because death certificates, the primary source for mortality data, are not always complete. They frequently contain what public health experts call “garbage codes”: vague or generic causes of death that are listed when the specific cause is unknown. Garbage codes make it difficult to track the toll of a disease over time or to look for geographical patterns in how people die. The data shown in the map above represents one research group’s effort to fill in these gaps.

That group — the Institute for Health Metrics and Evaluation — designed a statistical model that uses demographic and epidemiological data to assign more specific causes of death to the records containing garbage codes in the National Vital Statistics System, which gathers death records (and other information such as births) from state and local jurisdictions into a national database. The institute also age-standardized the data so that places with larger populations of older people, who die at higher rates, do not have inflated numbers. The result is a set of more complete estimates of mortality across the country, one revealing regional and local variations in causes of death.

Such regional trends are evident in the list of the 20 counties or parishes with the highest mortality rates. Rural Appalachia stands out; nine counties in Kentucky and three in West Virginia make the list. Rising cancer rates and increased deaths from substance abuse in Appalachia have kept mortality rates high there, even while overall mortality rates in the U.S. have gone down. After Appalachia, the region that features most heavily is the Dakotas. All of the counties in North and South Dakota in the top 20 (Buffalo, Oglala Lakota and Todd counties in South Dakota and Sioux County in North Dakota) are entirely or almost entirely made up of American Indian reservation lands. American Indian populations have historically suffered from poor health outcomes and challenges in health care access, contributing to high mortality rates.

Still, some outliers are simply anomalies. The county with the highest overall estimated mortality rate in 2014 was Union County, Florida. Union stands out from its neighbors in North Florida for a particular reason: It’s home to the Union Correctional Institution and the Florida Department of Corrections Reception and Medical Center, which provides inpatient medical care for state prisoners across Florida. These prisoners artificially raise Union County’s mortality rate.

As for the counties with the lowest mortality rates, 18 out of 20 fall west of the Mississippi. Colorado appears most often on the list, with six counties, including the three healthiest: Summit, Pitkin and Eagle. These counties lie adjacent to each other west of Denver, among the peaks of the Rocky Mountains. Many ski resorts and recreational areas fall within their borders.

Many of the counties with the lowest mortality rates are sparsely populated (the other two counties in the top five, Billings County in North Dakota and Hinsdale County in Colorado, both feature large swaths of federally protected land and in the 2010 census had fewer than 1,000 people), and others are particularly wealthy. Fairfax County, Virginia, and Los Alamos County, New Mexico, both had median household incomes above $100,000 in 2015.

Differing mortality rates between counties is only part of the story this data tells — we can also use it to determine how common a cause of death is. While rates for each cause vary significantly across the U.S., overall, Americans are much more likely to die from some causes than others.

The causes of death are ranked from most to least common in the table above. They range widely in impact: Cardiovascular diseases, the largest cause of death, resulted in about 250 deaths per 100,000 people in 2014, while there were fewer than 0.1 deaths per 100,000 from neglected tropical diseases. But the most recent mortality rate is only part of the story for any given cause of death. Deaths from cardiovascular disease in the U.S. have declined steadily since 1980, while deaths from other causes, such as neurological disorders (which include diseases such as Alzheimer’s and dementia) and mental and substance abuse disorders, have risen significantly. On the chart, the trend lines show which causes are on the rise and which are declining.

A note about these estimates

While accounting for “garbage codes” gives a clearer picture of mortality in the U.S., these estimates come with some uncertainty. For counties with very small populations or causes with few deaths, such as “forces of nature, war and legal intervention,” the uncertainty is greater. The impacts of Hurricane Katrina along the Gulf Coast in 2005 are obvious on the map, for example, but slightly higher rates also seem to spread across the country that year. An event as catastrophic as Hurricane Katrina can create a kind of ripple of mortality as people flee the disaster (resulting in a strain on resources elsewhere) or if people from other places happen to be in harm’s way at the time of the event (since deaths are counted in the county where people lived rather than where they died). But the slightly higher rates across the country are at least in part a side effect of the model, which sees such a dramatic rise in deaths in one place (the Gulf Coast) as an indication that otherwise similar places should also have higher mortality rates for that cause of death. The full data set for all causes of death, including uncertainty ranges, is available on the Institute for Health Metrics and Evaluation website.

The institute's data was also affected by changing administrative boundaries. In order to maintain consistency, counties that were newly split apart during these 35 years were kept intact in the analysis. This is most noticeable in Virginia, where many cities are administratively independent from counties but have the same mortality rates as the county surrounding them because they were evaluated together.

Cause of death categories

The cause of death categories in this project were developed by the institute for the Global Burden of Disease Study. They are mutually exclusive; no cause of death falls into more than one category. We will update the map above as the Institute for Health Metrics and Evaluation releases more detailed data for each category (data on individual cancers is already available). All causes of death included in this project are listed below.

Cardiovascular diseases: rheumatic heart disease; ischemic heart disease; cerebrovascular disease (including ischemic and hemorrhagic stroke); hypertensive heart disease; cardiomyopathy and myocarditis; atrial fibrillation and flutter; aortic aneurysm; peripheral arterial disease; endocarditis; other cardiovascular and circulatory diseases

Cancer: esophageal cancer; stomach cancer; liver cancer; larynx cancer; tracheal, bronchus and lung cancer; breast cancer; cervical cancer; uterine cancer; prostate cancer; colon and rectal cancer; lip and oral cavity cancer; nasopharynx cancer; other pharynx cancers; gallbladder and biliary tract cancer; pancreatic cancer; malignant skin melanoma; non-melanoma skin cancer; ovarian cancer; testicular cancer; kidney cancer; bladder cancer; brain and nervous system cancer; thyroid cancer; mesothelioma; Hodgkin lymphoma; non-Hodgkin lymphoma; multiple myeloma; leukemia; other cancers

Neurological disorders: Alzheimer’s disease and other dementias; Parkinson’s disease; epilepsy; multiple sclerosis; motor neuron disease; other neurological disorders

Diabetes, blood and endocrine diseases: diabetes mellitus; acute glomerulonephritis; chronic kidney disease; urinary diseases; gynecological diseases; hemoglobinopathies and hemolytic anemias; endocrine; metabolic, blood and immune disorders

Chronic respiratory diseases: chronic obstructive pulmonary disease; pneumoconiosis; asthma; interstitial lung disease and pulmonary sarcoidosis; other chronic respiratory diseases

Diarrhea and common infectious diseases: diarrheal diseases; intestinal infectious diseases; lower respiratory tract infections; upper respiratory tract infections; otitis media; meningitis; encephalitis; diphtheria; whooping cough; tetanus; measles; varicella-zoster virus infection; herpes zoster;

Self-harm

Interpersonal violence, excluding acts of war and terrorism

Unintentional injuries: falls; drowning; fire, heat and hot substances; poisonings; exposure to mechanical forces; adverse effects of medical treatment; animal contact; foreign body; other unintentional injuries; environmental heat and cold exposure

Cirrhosis and other chronic liver diseases

Digestive diseases: Peptic ulcer disease; gastritis and duodenitis; appendicitis; paralytic ileus and intestinal obstruction; inguinal, femoral and abdominal hernia; inflammatory bowel disease; vascular intestinal disorders; gallbladder and biliary diseases; pancreatitis; other digestive diseases

Transport injuries: road injuries; other transport injuries

Mental and substance use disorders: schizophrenia; alcohol use disorders; drug use disorders; eating disorders

Other non-infectious diseases: congenital anomalies; skin and subcutaneous diseases; sudden infant death syndrome

Neonatal disorders: neonatal preterm birth complications; neonatal encephalopathy due to birth asphyxia and trauma; neonatal sepsis and other neonatal infections; hemolytic disease and other neonatal jaundice; other neonatal disorders

Musculoskeletal disorders: rheumatoid arthritis; other musculoskeletal disorders

HIV/AIDS

Tuberculosis

Other infectious diseases: sexually transmitted diseases excluding HIV; hepatitis; other infectious diseases

Nutritional deficiencies: protein-energy malnutrition; iodine deficiency; iron deficiency anemia; other nutritional deficiencies

Maternal disorders: maternal hemorrhage; maternal sepsis and other maternal infections; maternal hypertensive disorders; maternal obstructed labor and uterine rupture; maternal abortion, miscarriage and ectopic pregnancy; indirect maternal deaths; late maternal deaths; other maternal disorders; maternal deaths aggravated by HIV/AIDS

Forces of nature, war and legal intervention

Neglected tropical diseases and malaria: malaria; Chagas disease; leishmaniasis; African trypanosomiasis; schistosomiasis; cysticercosis; cystic echinococcosis; dengue; yellow fever; rabies; intestinal nematode infections; other neglected tropical diseases; Ebola