SEATTLE — In tracing the blood line of her maternal grandmother, Martha Collins has gone six generations deep — back to 1870.

SEATTLE — In tracing the blood line of her maternal grandmother, Martha Collins has gone six generations deep — back to 1870.

In that year's census — the first after the abolition of slavery — the Seattle woman found her great-great-great-grandmother, a mixed-race woman named Violet Yeats, living with her husband and their four children on a plantation in rural Mississippi.

Widowed in the late 1800s, Violet shows up in every subsequent 10-year survey through 1930, when she lived with a granddaughter and great-grandchildren in Mississippi — the year before she died.

The Census Bureau last month released original data that its enumerators collected from 132 million Americans in April 1940 — opening another portal for Collins and the nation's growing number of family researchers to peer down their ancestral past.

The survey was conducted at a time when the nation was still feeling the effects of the Great Depression and at the dawn of World War II.

In the records from that year, Collins found Violet's granddaughter — Elnora White — living with her husband and seven children as sharecroppers on a farm in a small Missouri town.

Elnora had a second-grade education; her husband had attended school through third grade. None of their children — ages 1 to 18 — was enrolled in school at the time.

"It feels like I'm connecting with these ancestors, pulling their lives together," said Collins, 53, whose Seattle home has become a family repository of sorts, with photos of ancestors adorning the walls. "It gives you a glimpse into what their lives were like."

Every 10 years, the Census Bureau releases original records from 72 years earlier — previously confidential demographic data from individual survey forms.

These once-a-decade purges are highly anticipated by growing numbers of Americans looking to trace their family lines deep into the past.

Genealogy's growing appeal is evidenced by the popularity of such TV shows as "Who Do You Think You Are?"

The 1940 census data were the first to be released digitally, rather than on microfilm, putting this kind of research literally at people's fingertips.

"The release is a big deal when it comes out," said John LaMont, a genealogy librarian at Seattle Public Library.

The 1940 census data from some states have not been indexed fully to allow searches by name. But family researchers with some idea about where their relatives lived in 1940 can trace them.

While U.S. census data won't help you find Aunt Charlotte's home in Germany or Japan or Liberia or anywhere else overseas, the records are among the many tools researchers use to build a family mosaic.

They also rely on family stories, diaries and a host of public and private records, such as birth and death, church, school, property and military documents, and, increasingly, DNA — which can link distant relatives who have made their DNA profiles publicly available for matching in any number of databanks.

Still, try as she might, Collins has been unable to trace Violet Yeats — her great-great-great-grandmother — beyond 1870.

One obstacle has been trying to determine who Violet's parents were. Censuses before 1870 did not name slaves — if that's what Violet was — and noted their existence only by age and gender on a slave owner's plantation.

That year's census records show Violet's family with the surname Yeats — the name of the plantation owner they were linked to, which was common.

Sections of her death certificate that would contain the name of her mother and father — and could prove useful — list the response of the person reporting the death as "don't know." And the birth and death certificates of her children would list her maiden name and also could prove of value, but vital records are not public documents in some states, including Mississippi, where the family lived.

So, "Violet's case has simply gone cold," said Collins, a member of the Black Genealogy Research Group in Seattle. "It's been quite frustrating."

Part of the frustration is because Collins believes Violet holds the key to understanding connections she has made through DNA matches with relatives from other racial backgrounds in the U.S. and around the world — including a Jewish woman in Australia and another woman from the Dominican Republic.

A volunteer at the Northwest African American Museum, where she helps others with their research, Collins also is pursuing genealogy certification at the University of Washington. Her interest in family research dates to 1991, when her mother took ill and Collins worried that she and her siblings would lose their last connections to their past.

She has traveled across the country to visit relatives she's found in her search and has been to some of the towns where her ancestors once lived — walking the streets she believed they walked.

She visited the cemetery where Violet, her husband and other relatives are buried.

"To put it into context," Collins said, "you have to tie it in with history. If you don't study history, it won't make sense."

While Collins has become fascinated with Violet, that's not the only family line she's researched.

She traced her maternal grandfather to the arrival of his ancestors from England in 1634. Her paternal grandfather was born into slavery in Louisiana. After slavery was abolished, he remained as a sharecropper on the plantation, where his children, including Collins' father, were born.

Her father, who died in 1994 at age 85, had run away from home to join the Army after a falling out with the plantation mistress, who had put a bounty on his head.

Said Collins: "He figured the government's Army was the one place they couldn't get him."