Her death comes months after four men were hanged for the 2012 gang-rape and murder of a student on a bus in New Delhi, in a case that came to symbolise the nation's problems with sexual violence.
The victim's mother told the NDTV news channel that her daughter had been brought home and thrown in front of the house after the attack.
"My child could barely stand or speak," she added.
Officers said two men had been arrested on charges of gang-rape and murder, adding that the suspects may be tried in a fast-track court, without giving further details.
The incident took place in Balrampur district, around 500 kilometres away from where another Dalit woman was allegedly gang-raped by four upper-caste men last month.
The 19-year-old victim in that case was left paralysed by her injuries and was rushed to hospital in New Delhi 200 kilometres away but died on Tuesday.
She had gone missing on the morning of 14 September and was found brutalised hours later near her family's farmland. Four men were later arrested on charges of gang-rape and murder.
Her death sparked protests in Delhi and around Uttar Pradesh.
Police have imposed a security clampdown in the victim's village in Hatras district, a day after using force to disperse demonstrators who hit the streets after officers cremated her body without her family's permission.
Hundreds of officers in riot gear patrolled the village and barred people from gathering or meeting the woman's family members.
Opposition leaders arrested
The leaders of the opposition Congress party, Priyanka and Rahul Gandhi, were briefly arrested in Noida on the outskirts of New Delhi as they marched towards the woman's home.
Congress and other parties have criticised the Uttar Pradesh government over its failure to protect women, particularly those from the low-caste Dalit community. The state has reported several rapes in recent months.
Television footage showed Rahul Gandhi falling down on the ground as policemen jostled with his supporters before the two politicians were carried away in vehicles. They were later released.
The governing Bharatiya Janata Party accused its rivals of politicising the issue and promised the culprits would be dealt with under the law.
India's 200 million Dalits have long faced discrimination, and campaigners say attacks have increased during the coronavirus pandemic.
Women across the nation also continue to suffer alarming levels of sexual abuse.
An average of 87 rape cases were reported every day last year, according to data released Tuesday by the National Crime Records Bureau, but large numbers are thought to go unreported.
If you or someone you know is impacted by sexual assault, family or domestic violence, call 1800RESPECT on 1800 737 732 or visit 1800RESPECT.org.au. In an emergency, call 000.