I knew that Cornelius and Mary were buried in Hillside Cemetery, near Peekskill, New York, on the far northern edge of Westchester County. A transcription of the cemetery containing a record of their graves had been published by William P. Horton in 1928.  I located it several years ago on Ancestry.com. The entries for Cornelius are about halfway down the page below. As can happen with transcriptions, Mary Hannah's death date is incorrect. She died October 16, 1878, not 1885, as evidenced by her death certificate. 
On a research trip to Peekskill in 2011, I tried to find the graves. The Hillside Cemetery office is in a ranch style house on the cemetery property. Inside I found a nice woman who tried to look up Cornelius Currey's record on an ancient Gateway computer. She succeeded in finding his name, but there was no grave location listed. I spent at least an hour searching in fading light walking back and forth among the rows of graves with no luck.
In October, 2012, I brought Irene with me on another visit to Peekskill to look at graves in the old Van Cortlandtville Cemetery which is adjacent to the Hillside Cemetery. She has numerous ancestors buried in that cemetery, and we were able to view and photograph their graves and interesting stones.
As we were about to leave, I suggested we try our luck finding Cornelius and Mary Hannah once more. We parked by the Hillside Cemetery office and walked to the door. Inside was the same woman as before and the same Gateway computer. This time, when looking at the Curry listings (spelled without the 'e'), I noticed that one Curry entry had a grave location. (Isn't noticing often a key step in finding?) When I pointed it out, the woman used that Curry entry to find a 'Curry' folder in a creaky old file cabinet. Inside was a sheet of paper, the record of Plot 64, Block One, Avenue "C", which was the Curry family plot record containing Cornelius M. Currey, Mary Hannah Currey, four of their children and the husband of their daughter, Mary Elizabeth. 
With a plot number in hand the woman led us to a creased old map where she located and pointed out the Curry plot. 
We drove into the cemetery and parked on a narrow lane. A few minutes of searching led to the eureka moment - the Curry plot! 
The gravestone of Cornelius M. Currey is on the far right hand side of the plot.  As best as I can make out, the inscription reads :
Jan. 30. 1854.
aged 45 yrs 3 mos
& 28 dys.
The grave marker of Mary Hannah (Conklin) Currey is next to that of her husband.  The stone has come off its base and leans against it. The inscription reads:
DIED OCT. 16, 1878,
AGED 65 YRS. & 6 MOS.
In my excitment at finding the graves, I failed to notice that the brilliant October sun and a large tree/shrub had cast stark shadows on the stones when I photographed them. Darn! I'll need another trip to Peekskill to fix that.
 William P. Horton, Cemetery Inscriptions of Westchester County, N.Y. (1928), Vol. 2, Peekskill, p. 78; digital images, Ancestry.com (www.ancestry.com).
 Death Certificates, New York City Department of Records and Information Services (New York City, New York, Municipal Archives), Mary Hannah Currey; Brooklyn, New York; Health Department, City of Brooklyn Death Certificate; no. 08846; 16 October 1878.
 Hillside Cemetery (Cortlandt Manor, New York) plot records, Curry family plot record, block one, avenue "C", plot 64; photographed by Daniel Babish, 5 October 2012.
 Hillside Cemetery (Cortlandt Manor, New York) plot map, showing Curry family plot; photographed by Daniel Babish, 5 October 2012.
 Hillside Cemetery (Cortlandt Manor, Westchester County, New York), Curry family plot; block 1, avenue "C", plot 64; photographed by Daniel Babish, 5 October 2012.
 Hillside Cemetery (Cortlandt Manor, Westchester County, New York), Cornelius M. Currey grave marker; block 1, avenue "C", plot 64; photographed by Daniel Babish, 5 October 2012.
 Hillside Cemetery (Cortlandt Manor, Westchester County, New York), Mary Hannah Curry grave marker; block 1, avenue "C", plot 64; photographed by Daniel Babish, 5 October 2012.